An Australian zoo said Tuesday the birth of a southern white rhinoceros was a "sign of hope" for the species given the escalation of poaching in Africa.

Taronga Western Plains Zoo said the yet-to-be-named male calf was born to first-time mother Mopani in the safari-style animal park in Dubbo, 400 kilometres (250 miles) west of Sydney, on May 14.

"It seems the first rain we had in Dubbo in a number of months helped bring on the birth of this calf, which was spotted by a staff member on Tuesday morning," senior keeper Pascale Benoit said.

Taronga said every birth was important given unprecedented poaching in Africa, with close to 2,000 rhinos estimated to have been slaughtered since 2006, resulting in population growth slumping to some of the lowest levels in decades.

"He is a sign of hope to all of us to help stop the worst rhino poaching crisis in half a century," Taronga chief executive Cameron Kerr said.

The zoo hopes the delivery heralds a new start for its breeding programme after it last year suffered the devastating loss of four white rhinos from a mysterious illness which caused neurological abnormalities.

The cause of the disease has never been determined.

Mopani contracted the illness while pregnant but survived to give birth to the healthy 45-50 kilogram (99-110 pound) calf.

Zoo general manager Matt Fuller said nine white rhinos had been born at the facility since 2003 but the latest was "incredibly special" given the recent escalation in poaching, driven by demand from Asia for rhino horn.

"We are hearing that in excess of 300 animals have succumbed this year already," he said.

"If that's to continue then very soon, in fact something like 2015 or 2016, we will be seeing a tipping point where the deaths brought on by illegal poaching and hunting outweigh the number of births that are happening in the wild.

"And that really puts rhinos on one clear path, and that is the path towards extinction."

The zoo's rhinos are southern whites, the less endangered of the two white rhinoceros species. There are estimated to be some 20,000 southern whites surviving in the wild, according to environmental group WWF.