Northern corroboree frogs and koalas were returned to Tidbinbilla this week, after the animals were relocated to purpose-built facilities at the Australian National University.

Six koalas were brought back to Tidbinbilla on Wednesday evening, and five carloads of critically endangered northern corroboree frogs were brought back on Thursday morning.

Tidbinbillla threatened species program manager Dr Jennifer Pierson said 980 frogs were relocated in late-January.

She said staff at Tidbinbilla started to prepare for an evacuation in October as they forebode the extreme fire season ahead.

"The team was fully prepared and started the staging process at least six to seven weeks before we evacuated," Dr Pierson said.

"One of the things we wanted to make sure was that no matter who was on site they were available to come in and be able to identify which frogs were most important to take and be able to get them to ANU early."

About 1000 frogs remained on site at the special-purpose facility at Tidbinbilla due to space constraints. Dr Pierson said "genetically important" and "irreplaceable" ones were taken to ANU.

"It's hard to leave anything behind ... conservation is a tough job sometimes in that way," she said.

Tidbinbilla staff liaised closely with the Emergency Services Agency Incident Management Team and fire modellers to determine the appropriate time for evacuation.

Dr Pierson said the animals were evacuated about a day and a half before staff were no longer able to access the reserve.

The tiny corroboree frog is critically endangered and this has been attributed to the infectious chytrid fungus.

In 2003, the breeding facility was established at the Tidbinbilla Nature Reserve.

Some northern corroboree frogs from the Tidbinbilla breeding program have been released into the wild in Namadgi National Park at Mount Ginini, which Dr Pierson said was untouched by the fire.

"It was an incredible success and survival story for the frogs here," she said.

Minister for the Environment Mick Gentleman was on hand to reintroduce the species on Thursday. He said reinforcements to help protect from future fires have been put in place.

"We have used the animals' absence from Tidbinbilla to effectively prepare the facilities to be safer from the threat of fire," he said.

"Our teams have put in containment lines, removed vegetation around key enclosures and installed sprinkler systems in holding areas."

Brush-tailed rock wallabies and bettongs were also ferried out of Tidbinbilla and are due to return shortly.

There are also plans to bring back seven platypuses to ponds at Tidbinbilla. The mammals were sent to Sydney's Taronga Zoo due to drying waterways in December but recent rainfall has helped to fill the ponds.