A day after volunteers worked to divest and re-float eight pilot whales on Tuesday, they were aghast to find the animals stranded again on Wednesday along the beach shoes.

"When we left, they were floating. When we got back this morning, they were in the same place," John Mason, Department of Conservation (DOC) conservation services manager, was quoted by Fairfax NZ News.

Some 13 pilot whales were found stranded on a beach at the top of New Zealand's South Island on Tuesday. Rangers from the DOC as well as volunteers worked all day Tuesday to re-float eight of them away from the base of Farewell Spit. However, they were unable to group them together and moved out into the sea.

Five had died from the 13 whales, one on Tuesday afternoon and four overnight. The rescue operation had ran out of time because the sun had started setting down on them.

"It was getting to a point where we had to bring our staff and volunteers out of the water. So at that point, the whales were floating and pointing in the right direction," DoC's Takaka ranger Greg Napp said.

"They're swimming, they're in water that's deep enough they can go out. They could easily disappear and we'll never see them again or they could equally be back here in the morning."

When the sun shone, they were indeed back on the same spot. But Mr Mason believed things would be better on Wednesday.

"We'll have a go at getting them out mid-morning. We're hoping, with a boat, we can encourage them to go out. We'll give it our best shot."

"We are hoping we can get them afloat and further out to sea before dark when it would become unsafe for people to work in the sea trying to re-float the whales," Mr Napp said.