About 100 green and golden bell frogs have been born in a conservation program that aims to boost the endangered species.
Aussie Ark and the Australian Reptile Park established a breeding program for the species last year.
The frogs were bred at the reptile park's Conservation Ark facility at Somersby.
"These are the first green and golden bell frogs to have entered the program," said Jake Meney, the park's head of reptiles.
The program, done with Macquarie University, aims to breed the species in large numbers. It's hoped that the species will one day be returned to the wild.
Professor Rick Shine said there were "no plans for release at present".
"That will require permits from National Parks and Wildlife and it is a long and complex process," Professor Shine said.
"They will determine if we can release them and where. So the idea of a release is a long way off.
"They are not hard to breed. Indeed they were very enthusiastic and produced eggs as soon as we had warm wet nights - just the conditions that induce romantic thoughts in amphibians!"
Aussie Ark media officer Brodie Meney said the team was "quietly confident" the breeding program would be a success.
"It was great to see the tadpoles and now the metamorphs," she said.
Professor Shine said the frogs were abundant in Sydney only a few decades ago, but they now exist in "small isolated populations".
"Bringing back these spectacular amphibians would be a major step towards restoring degraded ecosystems."
Scientists partly attribute the decline and disappearance of some frog species to a disease caused by a chytrid fungus.
Researchers will also examine chytrid fungus and ways to boost frog immunity. The program involves a trial of chytrid immunity treatments.
Mr Meney said frogs are "incredible animals".
"They act as environmental health indicators, so the disappearance of our amphibian species is a definite cause for concern," Mr Meney said.
"Amphibians rights across Australia, unfortunately, are in rapid decline. Eight species of Australian frog have been considered a high risk for extinction in the next 20 years."
He added that conservation programs for the species are "incredibly important".
"In just a short time we have already had incredible success. We know that, long term, we can make a real difference to the species.
"Creating safe refuges for frogs in the wild and in captivity is the key to averting more species extinctions."
He said the program had a long way to go.
"In years to come, we're hoping to produce thousands of these frogs for release back into the wild."
The frogs are known for their bright green backs with gold patches. They can become dark brown when cold or inactive.
