The calf is the first for Cuddles and Mana, creating a new genetic bloodline.

Cuddles has been at Taronga Western Plains Zoo for 18 months.

During this time she had given birth to another calf which unfortunately did not survive.

Hippo keeper Carolene Magner said everyone at the zoo is keeping a close eye on the new family.

"It's very much early days still, but so far Cuddles is proving to be a good, attentive mother," Carolene said.

The calf weighs an estimated 40 kg.

It is yet to be named as keepers are yet to determine the gender.

"Hippos nurse their young underwater and whilst we haven't seen this behaviour, from everything we have witnessed the pair is bonding really well," Carolene said.

She said both Cuddles and the calf are spending most of their time in the water, with the calf staying close to its mum's side.

"Guests staying in the zoo at Zoofari Lodge on Thursday night were the first lucky people to see the new arrival, just moments after it was born," Carolene said.

"Currently mother and calf are in the middle paddock and pond just adjacent to the main Hippo Lake. Visitors can see the calf pop its head out of the water every now and then." Carolene said over the coming months, both keepers at the zoo and visitors will start to see the calf grow and develop.

"Hopefully it will start to come out of the water with its mother at feed time."