"The trough is to collect the blood," says Martin Brennan, tilting his lantern towards the gutter in the concrete floor. "Humans hold about 5 litres and it all needs to be drained."

Martin knows about such things. He also knows about apparitions, ectoplasm and EMF (Electro Magnetic Field) detectors, those ghost busting devices used for detecting 'activity'.

"Some of you will feel something tonight that isn't normal," he says, thrusting the EMP meter into my hands. "Thankfully, most of our ghosts are friendly." While I'm still pondering Martin's emphasis on the word 'most', we leave the morgue for the mass shower block, where the detectors begin to light up like Geiger counters. "The showers were a place of fear and trauma," Martin says. "On some nights you can still smell the carbolic acid."

Welcome to Q station Sydney Harbour National Park, one of Australia's most haunted sites and my home for the next two days.

Originally known as the North Head Quarantine Station the site was used from the 1830s to 1984 to isolate people migrating to Australia suspected of carrying contagious diseases. Today Q Station provides heritage accommodation housed across the 30-hectare Sydney Harbour National Park at North Head.

While other resorts offer swimming pools and day spas, this place is about history, heritage and paranormal things that go bump in the night. There are also little penguins, bandicoots and possums, a scalloped beach, a range of dining options, and recreational activities such as kayaking, stand up paddle boarding and bike hire. But the best part is its isolated bush setting, just 20 minutes from the Sydney CBD by fast ferry or 5 minutes from Manly Beach.

Isolation was the whole point of the exercise. If ships entering the heads had a sick patient on board they were required to hoist a yellow flag before disembarking all passengers, not just the infected ones. Here they were scrubbed within an inch of their lives, had their luggage autoclaved and were kept away from the local Sydney residents for several weeks or months. For healthy passengers, it was an extended holiday, for others it was a frightening experience of disease and death. In total 500 people died here.

My accommodation is the most isolated on the property - a Retreat Suite in the former Isolation Precinct, now a cluster of five renovated and refurbished rooms each with queen beds, ensuite bathrooms, separate lounge areas and balconies. The Retreat Suites also come with access to a communal lounge (for Retreat Suite guests only) making it the perfect escape for a group of friends.

Like the original passengers the accommodation is divided into deluxe rooms with ensuites (first class), heritage rooms with grouped, though private, bathroom facilities (second class) and a number of historic cottages once occupied by former Quarantine staff. All have been renovated with contemporary decor and come with flat screen TVs, bathrobe and slippers, balconies and alfresco furniture. It's a comfortable fusion of fresh, modern furnishings with nana's fittings and fixtures. The down side of the heritage theme is the lack of air conditioning, though the ceiling fans and screened windows do a decent job.

In reality, the rooms are just a base, all the good stuff is outside. On my first afternoon I kayak straight off the beach, paddling along the shoreline to a secluded cove, where a handful of yachts and a few fishermen have pulled in for shelter. Afterwards, I snorkel in the still waters beneath the wharf, the same wharf new arrivals would have come ashore by. A staff member tells me they saw stingrays the previous day, but I spot only a few small fish, even so, it is lovely swimming while looking across the harbour to the city skyline.

After lunch at the Engine Room Bar overlooking Quarantine Beach, we explore the rest of the property by bike, peddling past the gaggle of 65 heritage buildings, some former first, second and third class precincts, now accommodation, while others are officers' buildings, mess halls and pump rooms, now museums, recreation rooms and restaurants. Driving is prohibited, so guests must walk, bike or catch the shuttles to get around the extensive property. For some people, this could be a problem.

That evening we dine at the industrial chic Boilerhouse Restaurant and Bar, where the newly appointed executive chef Matt Kemp serves up a degustation of beetroot and goat's cheese tart, rabbit and quail terrine, poached Humpty Doo barramundi with wild mushrooms, grain fed sirloin and chocolate brownie with coffee gelato. Kemp, who ran his own restaurant Balzac for 12 years, has just launched a new menu that takes advantage of fresh, seasonal produce. "I aim to make Q Station a destination dining experience in its own right," he says. "Attracting both day trippers and overnight guests."

Being a national park Q Station welcomes day visitors to enjoy the historical site, dine at the restaurants, join a history or ghost tour or simply revel in the natural beauty of the beach and bush.

After the ghost tour of the hospital precinct I hit the hay about midnight, my sleep interrupted only by the murmur of the breeze through the gum trees, their craggy limbs creating silhouettes and scratching noises against my window screen. It's a comforting soundtrack, like a childhood camping trip.

The next morning I rise with the sun, keen for the beach yoga session before breakfast. Closing the door behind I step off the verandah, glancing back to see what kind of trees had disturbed my slumber. And then I notice – there are no trees near my window…

Yes, there is something strange in this neighbourhood.

TRIP NOTES

MORE INFORMATION

www.sydney.com

GETTING THERE

The easiest way to reach Q Station is by the Sydney Harbour Eco Hopper direct from Circular Quay. www.sydneyharbourecohopper.com.au. Alternatively take a ferry to Manly Wharf, then taxi or public bus 135, or drive (cars must be left in the car park).

STAYING THERE

Heritage Queen rooms, with grouped bathroom facilities, start from $199 per night. Retreat Suites start from $259 per night. 1 North Head Scenic Drive, Manly. Phone (02) 9466 1500, see www.qstation.com.au.

SEE + DO

Kayaking, Stand Up Paddle Boarding, bike hire and yoga can all be booked through the Visitor Centre (utilising outside operators). Snorkel gear is available for hire at the Visitor Centre ($10 for 1 hour), www.qstation.com.au. Ghost tours, including Ghost Trackers, Extreme Ghosts Tours and Paranormal Investigation Nights can be booked through www.quarantinestation.com.au.

Kerry van der Jagt was a guest of Q Station.