On Saturday February 27 a female arrived, which keepers named Zane, followed by a male on Tuesday March 8 called Amahle.

The duo join another two calves which were both born earlier in the year.

Keeper Simone Low said the four calves were a testament to the zoo's breeding program.

"Four births in the one year, so close together, it just shows how comfortable and relaxed the giraffe are. And it's bringing crowds in which help us educate people," Ms Lowe said.

There are currently less than 80,000 giraffe left in the world, she said.

The keepers were keeping an eye on the family dynamic, Ms Lowe said, as calves start to form a crèche.

"They love to play it's just like any young kids wanting to play in the playground they'll run up, say 'let's go, let's play' and then they'll run off and zoom around," Ms Lowe said.

"Just yesterday they were running around so much they didn't quite see one of the adults and nearly had a collision, they're having a good old time."

While giraffe usually give birth early in the morning, both Asmara and Tulli had their babies during the day.

"Asmara likes a bit of a spectacle her first calf was also born in front of everyone during our giraffe in focus," Ms Lowe said. 

"She's a very confident mother and Amahle's been having a good old time checking out his older siblings and just having a bit of a look."

Zane's birth means the zoo now has four generations of giraffe in the exhibit. Ms Lowe said just like with a family as long as they remain happy and relaxed they'll continue to procreate.