Scientists have rediscovered a spindly-legged toad species almost 90 years after it was last sighted in Malaysia's Borneo jungle, an environmental group said on Thursday.

The Sambas Stream Toad, or Borneo Rainbow Toad, was found by a team of scientists after months of scouring remote forest in Sarawak state on Borneo island, Conservation International (CI) said in a release.

The endangered toad was last seen in 1924 and was previously known from only three individuals.

"It is good to know that nature can surprise us when we are close to giving up hope, especially amidst our planet’s escalating extinction crisis," amphibian specialist Robin Moore of the Virginia-based group said.

"Amphibians are at the forefront of this tragedy, so I hope that these unique species serve as flagships for conservation, inspiring pride and hope by Malaysians and people everywhere," he was quoted in the release.

Malaysian researcher Indraneil Das set out with his team to rediscover the Sambas Stream Toad last August, searching after dark along the rugged ridges of a mountain range in western Sarawak state.

The toad was listed as one of the "World's Top 10 Most Wanted Lost Frogs" as part of a campaign by CI and another group to encourage scientists around the world to seek out amphibians that had not been seen in a decade or longer.

After months of combing through the jungle, the Sarawak team eventually discovered a small toad up a tree, which turned out to be the missing Sambas Stream Toad. In total, they found three individuals up three different trees.

"Thrilling discoveries like this beautiful toad, and the critical importance of amphibians to healthy ecosystems, are what fuel us to keep searching for lost species," Das was quoted in the release.

"They remind us that nature still holds precious secrets that we are still uncovering, which is why targeted protection and conservation is so important," he said.

Das already made headlines last year after he discovered Asia's tiniest frog, which is the size of a pea, in a national park in Sarawak state.

Sarawak and neighbouring Sabah states make up Malaysia's half of Borneo island, which is shared with Indonesia.