An adorable new addition has been welcomed at Monarto Zoo this week following the safe arrival of a "cheeky" newborn southern white rhino calf, with the birth described as a boost in the battle to save the endangered species.

Key points: A newborn Southern white rhino has captured keepers hearts on its first day at Monarto Zoo

A newborn Southern white rhino has captured keepers hearts on its first day at Monarto Zoo Imani is the sixth calf born at the Zoo and weighs around 50kg

Imani is the sixth calf born at the Zoo and weighs around 50kg The birth has been described as another boost in the fight to save the endangered species

Zoo keepers at the South Australian zoo met the calf on Monday morning, with the female — named Imani — born to mother Umqali overnight on Sunday.

Ungulate zoo keeper Haidee Kinter said the team had been preparing for the arrival but it came as a nice surprise on Monday morning.

She said the newborn had already shown its personality to keepers at the zoo and both mother and baby were doing well.

"They're pretty cheeky, every little baby we've had born out here … they make you laugh just by how cheeky they are," Ms Kinter told the ABC.

Imani the southern white rhino calf spent a lot of the day resting in the sun at Monarto Zoo. ( Zoos SA: Geoff Brooks )

"They're so inquisitive, they're nibbling at everything, she's already poking her tongue out when she's tasting all the things that are around her.

"Now that the calf has arrived we are very pleased that Umqali is being a fantastic mother and the pair are doing well and appear very relaxed."

Imani spent its first day capturing keepers' hearts at Monarto Zoo. ( Zoos SA: Geoff Brooks )

Ms Kinter said Umqali was pregnant with Imani for just shy of 17 months, with the newborn displaying its unique features to keepers on day one.

"They've got these four — we always describe them as dinner plates — these huge big sort of flip-floppy feet that look really out of proportion," she said.

"[And] these great big ears that are moving around like satellite dishes."

While Imani may be at an adorable size for the moment, Ms Kinter said it would not last long, with newborn rhinos generally doubling in size within two weeks.

"They're roughly sitting between 40kg and 55kg when they're born and she is certainly a solid little girl so I'd say she's around the 50kg," she said.

"History tells us they will probably double in size in the first two weeks so she will be close to 80kg by the time she's two weeks old.

"They're drinking 16 litres of mum's milk a day and gaining two to three kilos a day roughly … they get really big really quickly."

Ms Kinter said Imani was expected to grow to around 1,000kg within its first two years and would grow to between 1,500kg-2,000kg when fully grown.

Working to save the endangered species

Imani is the sixth calf born at Monarto Zoo, with the mother and daughter duo currently on exhibit along with two other rhinos, named Uhura and Savannah.

Imani stayed close to its mother on Monday. ( ZOOS SA: Geoff Brooks )

Monarto Zoo director Peter Clark said the safe arrival of another newborn calf was an excellent achievement and showed the international breeding program was working to save the endangered species.

"We are absolutely thrilled to welcome this beautiful young calf to Monarto Zoo and pleased that her arrival is contributing to the insurance population of such a remarkable species," Mr Clark said.

"Sadly, with the poaching rate now exceeding the birth rate of rhinos in Africa, it's heartbreaking that rhinos are facing some serious trouble in the wild, experts predict that if we don't act now, they may be extinct in less than 10 years."

Zoos SA has joined The Australian Rhino Project which plans to bring a large number of rhinos to Australia in the next few years, with the hope of bringing a rhino sanctuary to life at Monarto Zoo.