Believed to be two to six months old and about 2.5m (8ft) long, the orphan could not survive alone in the ocean.

His fate gripped the nation, with hundreds of people volunteering to help the nationwide search.

Toa - Maori for "warrior" - was separated from his pod and found by two teenagers in a rockpool in Plimmerton, north of Wellington.

Conservationists placed him in a makeshift pool, where he was fed via a special teat every four hours.

A fleet of aircraft and on-shore observers scoured hundreds of miles of coastline for Toa's pod in the hope his mother could be found.

But Whale Rescue, an organisation that had been helping care for Toa, said his condition suddenly deteriorated on Friday. Vets rushed to help but were unable to save him.

"We have to report that a little time ago Toa passed away," the organisation said. "As you can all imagine we are devastated."

The team had hoped to reunite Toa with his mother, or if that failed, have him adopted by another pod.

Ian Angus, marine species manager at the Department of Conservation, said Toa's carers "threw everything at trying to save him".

"We were always aware that the longer he was in captivity, away from his mother, the more likely it was that his health would deteriorate," Mr Angus said.

"Toa passed quickly, surrounded by love, with his last days made as comfortable as possible."