A species once thought to be extinct, the Western Australian dibbler, has reached a milestone, with Perth Zoo weaning its 1,000th baby under a repopulation program.

The zoo has been working since 1997 to re-establish numbers of the tiny marsupial in WA, after introduced predators and habitat loss saw their populations severely dwindle.

Zookeeper Lesley Shaw said staff did not normally name baby dibblers but they made an exception for the 1,000th, naming him Miles.

"It's always very exciting when you get to a milestone and this is certainly one of those," she said.

"Miles weighed 33 grams so he was the biggest one of the litter. Very robust little fellow."

At only four months old, Shaw said Miles had just weeks left at the zoo until he and his seven siblings were released into the wild.

"They're not with us for long and that's good because they need to get back into the wild and display their natural behaviour," she said.

The breeding program is the only one of its kind in the world.

The zoo has so far released about 850 dibblers into the wild.

"They're strong and tough little creatures and they deserve a lot of credit," Shaw said.

"They're very little but in the scheme of things they're a pretty big thing out there."

Dibblers face short mating window

The eight dibblers are due to be released into the wild within weeks. ( ABC News: Dominique Bayens )

Native breeding program supervisor Cathy Lambert said dibblers were only able to mate for three or four days of the year.

"It was really important for us to be able to work out exactly when they're supposed to be mating so we could get them together at the right time," she said.

Ms Lambert hopes to continue breeding the marsupials until they are able to sustain themselves in the wild.

"The end goal is to do ourselves out of a job," she said.

"That's happened with a couple of other species we've worked with in the past and we're hoping it will go the same way with the dibblers as well."