In a stark demonstration of how sharply his double dissolution strategy backfired, the final picture of the 45th Parliament shows a Prime Minister pared back to a one-seat majority in the House of Representatives, and down another three senators upstairs where the crossbench has swelled by the same number.

The outcome has delivered inordinate power to the polar extremes of Australian politics, at the expense of the centre, on all but uncontroversial legislation over which government and opposition agree.

This means Mr Turnbull's programs, such as his bitterly opposed union reform bills used to trigger the double dissolution, the divisive same-sex marriage plebiscite, and hotly contested superannuation changes, could now be held hostage to minor party ransom.

There are also strong protectionist and anti-climate-change pressures building with both One Nation, and the Nick Xenophon Team associated with policies favouring local manufacturing, increased industry protection, and strong opposition to foreign investment in Australian agricultural land.

The outcome of the July 2, election came as Mr Turnbull and Treasurer Scott Morrison bowed to public and opposition pressure by demanding that the nation's big four banks answer to Parliament on a regular basis to explain their interest rate policies.

With Labor pushing strongly through the campaign for a banking royal commission amid widespread public anger at high interest rates as well as other fees and charges, the banks' decision this week to pass on just part of cash-rate reduction to borrowers, brought that pressure to a head.

After Mr Morrison had initially resisted strongly criticising the banks, preferring to leave them to answer for commercial decisions, Mr Turnbull stepped up his condemning rhetoric on Wednesday and then both men ratcheted those reactions up again on Thursday announcing that the banks will be required to front up to Parliament's economics committee.

Mr Turnbull promised "ongoing permanent cultural change" and "change that will make the banks ensure that they are accountable and the committee will seize on this reference".

"It will, just as it has done with the RBA and APRA, you will get this change in culture so the banks will know then that if they decide not to pass on an interest rate cut from the Reserve Bank they will know that they're going to have to front up to a House of Representatives committee and explain that and take questions about that and justify their actions in front of the elected representatives of the Australian people," he said in Sydney.

Opposition leader Bill Shorten was unimpressed, calling the impact on the powerful institutions "pathetic".

"Yet again he has just wagged his finger at them and delivered another empty lecture. He is too weak and his government is too divided to stand up to the banks," he said.

With the configuration of the Parliament now clear, interest is turning to the potential fate of various government bills.

Of prime interest are the two "trigger" bills to restore the Howard-era watchdog, the Australian Building and Construction Commission, and a separate bill known as the Registered Organisations bill.

Some in the government say the bills might even get through without a joint sitting, given that almost all of the new and returned crossbench senators favour them.

However if not, the government could struggle to get the 114 votes needed in a joint sitting after losing three senators and 14 lower house MPs. While Senator Xenophon has offered qualified support for the ABCC bill, he wants amendments and that would contravene the rules dictating that the joint sitting can only consider identical legislation to that initially blocked.

The overall outcome is a repudiation of Mr Turnbull's plan to clear out the Senate crossbench via the double dissolution election.

"A double dissolution is a very dangerous path to tread if you're trying to get a decent position in the Senate," election analyst Antony Green told the ABC on Thursday.

The numbers in the new-look Senate are as follows: Coalition 30, Labor 26, Greens 9, One Nation 4, Nick Xenophon Team 3, plus Jacqui Lambie, Derryn Hinch, the Liberal Democratic Party's David Leyonhjelm and Family First's Bob Day.

In NSW, the Greens retained senator Lee Rhiannon, meaning the left-wing party will have nine senators and will also hold the balance of power in some circumstances, able to pass government bills without the help of Labor or the crossbenchers.

However, as Green told the ABC: "One Nation has a very poor record of keeping their [MPs] in the party for a full term. They've tended to split very quickly."

The country's newest Hanson-aligned senators are former coal mine manager Malcolm Roberts from Queensland and long-time party executive Brian Burston from NSW.

Mr Roberts, a leader of climate sceptic group the Galileo Movement, wants climate scepticism taught in schools and believes CSIRO scientists have conspired with the United Nations to produce "corrupt" reports on climate change.

Mr Burston, a former Cessnock councillor who acknowledged he was a "last-minute" candidate, describes Islam as "an infringement on our culture".

"We're a Christian country, I know we have some Jews as well … but the Muslims, they kneel five times a day and it's not how we are in this country," he told News Corp.

One Nation's policy agenda calls for a royal commission into both Islam and climate science, and advocates the abolition of the Renewable Energy Target.

It is 20 years since Ms Hanson entered Australian politics by winning the lower house seat of Oxley, and used her maiden speech to lament that Australia was being "swamped by Asians".

Mr Leyonhjelm scraped home in the last NSW Senate spot on a pro-gun, pro-smoking, anti-regulation policy platform. In the last Parliament he established an inquiry into the "nanny state" to examine government intervention in personal choices.

With Michael Koziol

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