Almost two dozen wallabies have been flown to a national park in Western Australia to boost a tiny population of the threatened species.

Two black-flanked rock wallabies and their joey created a stir after they were spotted by rock climbers in a remote gorge in Kalbarri National Park last year, decades after they were thought to have become locally extinct.

Staff from the Department of Parks and Wildlife (DPAW) spent days trekking through the park in the search for other surviving wallabies, but did not find any.

But the trio now has company: 23 wallabies have been sent in from bulging populations in the Wheatbelt.

DPAW principal research scientist Dr David Pearson said so far, the animals seemed to have taken well to the rugged sandstone gorge.

"They certainly bolted off the flat and onto the rocks and immediately looked at home," he said.

"They've come from granite rocks and they were going onto sandstone, their footing was good and away they went and disappeared into crevices."

The translocated wallabies were from populations at Nangeen Hill and Mount Caroline, where they were breeding so well, they were beginning to overgraze.

Unique genetics mark Kalbarri population

DPAW spent months carefully analysing the Kalbarri animals and discovered the pair had unique DNA, most closely linked to wallabies in the Little Sandy Desert, almost 1,000 kilometres away.

To try to preserve the distinctness of the genes, the 23 wallabies have been released in two areas — three females have been positioned near the existing trio, while the 20 others have been released further along the gorge.

"We didn't want to swamp the Kalbarri animals with a whole bundle of Wheatbelt ones, so that's why we just put the three females in with the Kalbarri animals and the other rock wallabies further downstream," Dr Pearson said.

"Over time, if the population grows they will come together and so the rock wallabies will interbreed and we'll see those Kalbarri genes maintained."

Automatic cameras are being used to track how the animals respond to their new home and predators roaming in the area.

Each wallaby is also fitted with small radio collar.

Dr Pearson said if the animal was still for 12 hours, an alert was sent to the DPAW staff closely monitoring them.

"If for some reason any of them die, we can immediately go in there and work out why," he said.

"It's like a crime scene in a way; if you find a dead wallaby you want to go in there and work out what was responsible for its death so we can continually learn from the whole process."

It is believed overgrazing feral goats and predators like cats and foxes led to the demise of what was a healthy population of animals in the area decades ago.

DPAW has been baiting the area for foxes since 1996 and carried out a goat culling since 2006.