It's home to some of Australia's most endangered native marsupials - some of which became extinct on the mainland more than 100 years ago.

The 420-hectare Mount Rothwell Conservation and Research Centre is the largest predator-free ecosystem in Victoria.

A pioneering Werribee family, the Chirnsides, bought the land in 1859 and used the woodlands as a polo field, farming the rest of the estate.

The property is now exclusively managed for the conservation of some of the country's most threatened species, with some of its animals forming the largest remaining free-ranging populations in the country.

They include the eastern barred bandicoot, the brush-tailed rock wallaby and the eastern quoll.

A predator, the quoll was once hunted for a halfpenny bounty and has been extinct in Victoria since the 1930s.

The centre operates breeding and research programs with government wildlife agencies and research organisations, including the Department of Sustainability and Environment, Zoos Victoria, Monash University and the University of Melbourne.

Established as the Little River Earth Sanctuary in 2000, it was bought by a company co-founded by controversial environmentalist Dr John Wamsley, known for wearing a hat made from feral cats.

After a series of financial difficulties, his company was forced to sell and the property has since changed hands.

When the new owners bought the property 18 months ago, they abandoned the initial dreams of operating the centre as a commercial eco-tourism venue.

However, guided night walks are held on the last Saturday of the month and can be arranged any night for groups of 10 or more, while there are regular school tours.

It's a cold and wet night when the Banner visits. As we gather in groups, we are told some of the animals will bunker down as a result of the weather conditions, so it's highly unlikely we'll be able to see the full complement.

The sanctuary has the only surviving old-growth woodland in the area, with trees dating back 200 years, beautifully intact granite hills and remnant grasslands with critically endangered flora.

As we move off towards the woodlands, we spot a red-bellied pademelon, a small marsupial now found in the wild only in Tasmania since it was killed off by foxes on the mainland.

Further down the path, our guide shines her spotlight at a rufous bettong, a marsupial about 80 centimetres in length with red-brown fur, which we are told can hop like a kangaroo and jump up to 1.2metres high.

In the early 1900s, it became extinct in Victoria, along with other species of bettong that proved easy prey for foxes and feral animals.

After spotting a few eastern grey kangaroos and a red-necked wallaby, we head deeper into woodlands where we learn about the six species of bats that call it home.

We spot eastern quolls, the southern-brown bandicoot and the long-nosed potaroo, a 20-centimetre high kangaroo-like creature, which has been recognised as one of the state's threatened species.

The entire property is enclosed by a 12-kilometre electric predator-proof fence, which is inspected daily and monitored by a computer controlled telemetry system. At two metres, it's enough to stop a leaping fox and discourage feral cats.

At the bottom of the fence, wire netting along the ground dissuades burrowing rabbits.

The sanctuary has provided its rare marsupials, including quolls and eastern-barred bandicoots, with the chance to breed in the wild again.

DOING WELL<.b>

ONE of most remarkable success stories among the animals at Mount Rothwell has been the brush-tailed rock wallaby.

Seven years ago, there were less than 10 in the wild, but in 2004 representatives from the sanctuary rescued eight from a small island north of Auckland - where they were regarded as a feral species - and introduced them to Mount Rothwell.

Their numbers have now grown to more than 30.

Site manager Paul Mervin has developed a deep affection for the animals at the sanctuary and its work to ensure their survival for future generations.

"I love being here - it's always a pleasure," he said.

"There's a great sense of responsibility that comes with it, but there's no better feeling than being able to save our wildlife."

The centre is at 5 Mt Rothwell Road, Little River.

Night walks cost $20 for adults and $10 for children. For bookings, phone 0434295355 or for more information visit www.mtrothwell.com.au