An Australian-British dual national was aboard the missing EgyptAir jetliner, Australian Foreign Affairs Minister Julie Bishop says.

Ms Bishop said Australia was closely working with British authorities who are providing consular assistance to the man's family.

"My thoughts are with the families and friends of those affected," Ms Bishop said in a statement on Friday.

The revelation comes as EgyptAir says the wreckage of its missing plane with 66 people on board has not been found, despite earlier announcing debris had been located in the Mediterranean Sea.

"We stand corrected on finding the wreckage because what we identified is not a part of our plane. So the search and rescue is still going on," EgyptAir vice-chairman Ahmed Adel told CNN.

The airline had earlier released a statement saying the plane's wreckage had been found near the Greek island of Karpathos.

The confusion was compounded when the Egyptian Civil Aviation Ministry said Greek authorities had on Thursday found "floating material" and lifejackets likely to be from the plane.

"All I will say is that our embassy in Athens told us that it was contacted by Greek authorities, who signalled that they found white and blue debris corresponding to EgyptAir's colours," Egyptian ambassador to France Ehab Badawy told France's BFM television.

Greek defence sources told Reuters they had found pieces of plastic and two life vests in the sea 370 kilometres south of the island of Crete, but sources said the material they had found so far was not blue and white.

Missing flight

Flight MS804, an Airbus A320, took off from Charles de Gaulle Airport in Paris at 11.09pm on Wednesday (7.09am AEST), and was due to land in Cairo at 3.15am on Thursday. However, it vanished from radar and never arrived.

The plane, with 56 passengers and 10 crew members, most likely plunged into the Mediterranean about halfway between the Greek island of Crete and Egypt's coastline, or about 280 kilometres offshore shortly before it was scheduled to land.

The plane had made "sudden swerves" immediately after it entered Egyptian airspace, then dropped 22,000 feet before it disappeared, the Greek Defence Minister Panos Kammenos said.

A child and two babies are among those on board.

The Egyptian Civil Aviation Minister, Sherif Fathi, told a news conference in Cairo that it was premature to draw conclusions about the cause of the plane's disappearance, but he acknowledged that it might be terrorism.

The passengers are from 12 countries: 30 from Egypt, 15 from France, two from Iraq and one each from Britain, Canada, Belgium, Kuwait, Saudi Arabia, Sudan, Chad, Portugal and Algeria. The crew comprises the pilot and co-pilot, five cabin crew and three security staff.

The pilot Mohamed Saeed Shaqeer, 36, had 6275 hours of total flying time, including 2101 hours at the controls of an Airbus 320 like the one used on the Paris to Cairo flight, The New York Times reported a spokeswoman for the CIvil Aviation Ministry and EgyptAir as saying. The co-pilot, Mohamed Ahmed Mamdouh, 24, had 2766 flying hours, the airline said.

An Egyptian Interior Ministry official said the men had no known political affiliations, and had passed their periodic background security checks.

A Cairo Airport official, who spoke on the condition of anonymity, described Mr Shaqeer as kind and responsible.

He dismissed any suggestion that either of the pilots might have downed the plane, calling the idea preposterous.

The dual national

Ms Bishop did not name the Australian-British dual national on the missing flight. However the only British national identified among the 66 people on board MS804 is Richard Osman, 40, a geologist who had just welcomed the birth of his second child.

Mr Osman was flying to Cairo on MS804 for his job as a geologist with an Egyptian goldmining company, his brother, Alistair Osman, told the South Wales Evening Post.

Alistair said his brother had previously worked in goldmines in Australia, before returning to Europe several years ago. He lives with his family in Jersey, in the Channel Islands.

Mr Osman's French-born wife Aureilie, 36, gave birth to the couple's second daughter Olympe on April 27. Their first daughter, Victios, is aged one.

"Of all the family I would've thought Richard would have been the last to go," Alistair told the South Wales Evening Post.

Mr Osman's wife and children are in Paris, where the couple have a home.

Leaders weigh in

In brief remarks before a conference in Paris, French President Francois Hollande said the plane had crashed.

"The information we have managed to gather - the ministers, members of the government and the Egyptian authorities - confirm alas that this plane had crashed," Mr Hollande said.

He said the French government's "thoughts and compassion and solidarity" were with the families of all those on board.

Hillary Clinton, the Democratic frontrunner in the US presidential race and a former US secretary of state, said that, based on preliminary information, "It does appear it was an act of terrorism - exactly how, of course, the investigation will have to determine."

However, a US review of satellite imagery so far has not produced any signs of an explosion aboard the EgyptAir flight, officials from multiple US agencies told Reuters.

The officials, who spoke on condition of anonymity to discuss intelligence matters, said the conclusion was the result of a preliminary examination of imagery and cautioned against media reports suggesting the US believed a bomb was responsible.

The US had not ruled out any possible causes, such as mechanical failure, terrorism or a deliberate act by the pilot or crew, they said.

Intelligence analysts who monitor jihadi websites and social media said there had been no claims of responsibility by terrorist groups.

Greek, Egyptian authorities

The head of the Greek civil aviation authority told CNN that the last contact with the plane and air traffic controllers was as the plane passed over Kea, near Athens.

When they tried to contact the pilots again 16 kilometres before the plane left Greek airspace they did not get a response, despite trying for 1½ minutes.

The twin-engine aircraft was delivered to EgyptAir in November 2003 and had accumulated 48,000 hours of flying time, according to data compiled by flightradar24, an aviation website. The aircraft's itinerary in the past two days, the website showed, had taken it on round trips between Cairo and Asmara, Eritrea, and between Cairo and Tunis. Then it flew to Paris.

Officials in Egypt, who have been under intense scrutiny since a bomb brought down a Russian airliner over the Sinai Peninsula in October, killing all 224 people on board, declined to describe the events on Wednesday as a crash.

The Aviation Minister's quick acknowledgment that terrorism might be a cause this time was in stark contrast to the government's handling of the loss of the Russian airliner.

In a flurry of posts on Twitter on Thursday, EgyptAir emphasised the experience of the crew of the missing airliner. The pilot had more than 6000 flying hours, and the co-pilot had 2700 hours, the airline said.

The aviation authority has booked a hotel in Cairo for families of those on board the plane and has offered free tickets to family members in Paris so they can come to the centre of operations in Cairo.

The families' wait

In the hours after the plane disappeared, distraught family members arrived at Cairo and Charles de Gaulle airports to find out more information.

Egypt and Greece launched their search for the plane about 200 kilometres south-east of Karpathos.

A merchant ship captain earlier told media he had seen a "flame in the sky" in the same region.

The Canadian government said on Thursday that two Canadian citizens were aboard and Foreign Affairs Minister Stephane Dion said Canadian officials were working with authorities to confirm if any other Canadians were on the flight.

The US State Department said there was no indication that American citizens were on board.

At Cairo Airport, a man sat on a brown leather couch crying with his hands covering his face.

"How long will Egypt live if human lives are so cheap?" he said.

The mother of a flight attendant rushed out of the VIP hall where families waited in tears. She said the last time her daughter called her was on Wednesday night.

"They haven't told us anything," she said.

Some relatives tried to beat up a photographer working for EgyptAir who took several pictures of the families waiting in the hall.

Security officials intervened and escorted him out.

With its archaeological sites and Red Sea resorts, Egypt is a traditional destination for Western tourists. But the industry has been badly hit by the downing of a Russian Metrojet flight last October, in which all 224 people on board were killed, as well as by an Islamist insurgency and a string of bomb attacks.

A320s normally seat 150, which means the EgyptAir plane was barely a third full.

Airbus said the missing A320 was delivered to EgyptAir in November 2003 and had operated about 48,000 flight hours.

AP, Reuters, Megan Levy, Georgina Mitchell, New York Times, Josephine Tovey