A strong southerly wind is blowing smoke from the fire out to sea.

It is not known how the fire started at this stage. An investigation will take place to determine the cause.

Helicopters battling the blaze were grounded yesterday evening at 8.30pm.

The fire was burning through pine slash and regrowth, a Fire and Emergency spokesperson said.

Daytrippers feared getting trapped

Tarah Spyve told the Herald she could not drive back along Black Jack Rd because of the fire. She later said firefighters began allowing cars through five at a time about 8.30pm.

While Spyve was trapped, she said there was no shop to buy food from.

A local allowed the strandees into their home to fill up their water bottles, she said.

A Fire and Emergency NZ spokeswoman said the fire service would be closing Black Jack Rd overnight. She said Fire and Emergency was not aware of anyone being trapped by the road closure.

Police were also unaware of reports of people being trapped and were not involved in responding to the blaze, a spokeswoman said.

A witness told the Herald he could see flames atop the hills between Kūaotunu and Ōtama Beach. He described “huge smoke” billowing from the fire.

He said motorists were being stopped from driving down Black Jack Rd.

A holidaymaker in the area could see the flames and smoke while he was out on the water.

“It’s like a volcano,” Connor Le Vert told the Herald.

Le Vert described the smoke as being a yellow colour and said he could see bright red flames on the top of the hill.

“We can see smoke coming out. There’s a tonne of smoke coming off,” Le Vert said.

“We could see flames, bright red flames at the top of the hill.“We saw firefighters climbing up the hill.”