A long running debate about the identity of the largest ever bird may have been put to rest by British researchers. The top spot being awarded to a distant relative of the flightless New Zealand kiwi.

Vorombe Titan, roaming the Madagascan island 500,000 to 1 million years ago. Source: Jaime Chirinos / Royal Society Open Science

Named the Vorombe titan, Malagasy for "big bird", it's part of a group known as elephant birds that once roamed the African island of Madagascar around 1000 years ago.

The study published in the journal Royal Society Open Science, describes the now extinct creature as weighing up to 800kg and towering over people at three metres tall, Newsweek reports.

New analysis of elephant bird bones from museums around the world revealed "unexpected diversity"in the Madagascan behemoths, according to Newsweek.

The study found that the group was actually divided into at least four different species.

The distinct differences in bone size and shape merited a new genus name, Vorombe. The colossal elephant bird belonged to the same family of flightless animals that today includes the kiwi, emu and ostrich.

"Elephant birds are a radiation of extinct, giant, flightless birds unique to the island of Madagascar.