Two whales stranded on Northland's Ripiro Beach

Two humpback whales will remain stranded at a Northland beach overnight.

The two whales are both alive and are being kept wet and upright at Ripiro beach, south of Bayly's Beach, said Department of Conservation (DoC) spokesperson Leigh-Anne Wiig.

DoC staff have not been able to re-float the whales in the high tide at 4pm, meaning the animals will have to stay on the beach until Monday.

Stephen Soole, the operations manager of DoC's Kauri Coast office, said the whales were calling to each other and believes they are a mother and calf.

Gordon Morfett, a resident who was down at the beach and saw the whales, told Newshub one of the whales looked very weak.

"The one that's closer is in a bit of a hole; he was the weakest one," Mr Morfett explained.

"But the next one out was on a sandbank - and while it was closest to the sea, it's probably gonna be the more difficult one to get re-floated again."

Ms Wiig said the pair were approximately 10 to 12 metres in length, while Mr Morfett said they would weigh roughly 15 to 20 tonnes.

"They stand up to about your chest high, perhaps a bit more, when they are sitting on the stand," said Mr Morfett.

He said the tide was coming in, making it more difficult for helpers to keep the whales upright.

Local resident Josie Scott said a karakia had been said for the whales.

Newshub.