Orca stranding: Whales refloated following frantic rescue effort in Kaipara Harbour

A dramatic orca stranding in Auckland's Kaipara Harbour this afternoon has had a happy ending after the 11 whales were re-floated.

The Department of Conservation confirmed in a tweet just before 7pm that the group had been re-floated from the sandbar with the rising tide.

"It is believed they were chasing food and became stranded ... big thanks to the boaties who kept the whales cooled and also to @ProjectJonah and the Orca Research Trust."

The stranding occurred about 1.5km to 3km south-west of South Head.

Some of the stranded orca before they were refloated. Photo / Supplied

First to the rescue of the eight adults and three calves were a group of 10 snapper fishing buddies on charter boat Ali-Kat who, armed with fishing buckets, jumped on to the sandbar to help about 1.30pm.

Hillsborough man Marnix Kelderman was among the nine men and one woman on Ali-Kat, which was skippered by Ali-Kat Charters' owner Wayne Kostanich.

"We saw what looked like dorsal fins on the water. [The whales] were highly distressed, flapping their tails. The young were screaming. A couple of the big ones had rolled over and their blowholes were covered.

"They were effectively drowning."

The orca became stranded on the outgoing tide. Photo / Supplied

Another three were in such a bad way they were not moving at all, he said.

Orca Watch and the Coastguard were called but told the group they would not be able to get to the stranding for a few hours.

So Kostanich dropped the anchor and he and nine of those on board - all Aucklanders involved in the building industry - jumped into the then waist-deep outgoing tide to help, Kelderman said.

"We're just friends who go on a fishing trip ... there's a painter, builders, an alarm specialist. I'm a forensic scientist."

They used fish buckets to keep the whales wet as the water dropped down to ankle-deep before the tide turned.

But all 10 helpers were needed to turn over the whales which had rolled.

"They were pretty hard to roll over. We all put our backs into it."

People who had been fishing on the Ali-Kat helped the orca following the stranding. Photo / Supplied

However, he believed the whales were trying to help their rescuers, the 52-year-old said.

"They were swivelling their tails to help. Beforehand it had just been uncoordinated whipping."

Everyone was careful to be aware of the whales' tails and to stay clear of their mouths, he said.

"You didn't feel you were in danger. At no stage did I feel like we were at risk."

And despite the effort involved from 1.30pm until a boat armed with hoses arrived at 4.15pm, he didn't feel tired, Kelderman said.

"We just jumped in and then suddenly you realised an hour had gone. The time went really quickly."

It was a good feeling to know the group had been able to help.

"I've never done this before - it's the kind of thing you see on TV."