Tiny kiwi egg found in central North Island

The brown kiwi egg weighs just 217.6g.

Conservationists say a tiny kiwi egg found in the central North Island is the smallest of its kind.

The brown kiwi egg weighed just 217.6g when it arrived at Rotorua's Rainbow Springs Kiwi Encounter conservation centre last week from Whirinaki Forest.

The clutch it came from produced only one other egg - weighing a much more normal 442.1g.

Claire Travers, husbandry manager at the centre's Kiwi Encounter, said the contents of the small egg already had a name - Mini.

Today is the 68th day of incubation and the egg is on schedule to hatch before the end of the month.

Ms Travers said it was the smallest brown kiwi egg the centre knew of. The previous smallest weighed 292g at the same stage of incubation.

"This arrival is one of the most eagerly awaited in some time," she said.

It was a mystery why the mother had laid such a small egg, Ms Travers said.

"Possible factors are that it is diet-related or it could point to issues with her ovaries or reproductive tract. Whatever caused Mini to be laid, he or she can be assured of the very best care come hatching time."

Cameras have been installed at the centre and intensive care specialists are ready to help with the hatching.