All Blacks captain Richie McCaw had a new fight on his hands last night, joining dozens of helicopter pilots battling frost in Marlborough.

The mercury dipped to below freezing in the Southern Valleys, Waihopai, Fairhall and the Wairau Valley overnight, with Fairhall the coldest at -0.6 degrees Celsius. With bud burst complete in the district's vineyards, winegrowers were doing everything they could to protect their crop from frost damage. Enter Richie.

Windrush Vineyard manager Callum Linklater had been up all night, with helicopters flying from about 1am to 6.30am. When he called his regular helicopter company, he had no idea that one of the pilots would be New Zealand's favourite rugby star.

Richie McCaw/ Facebook All Blacks captain Richie McCaw in front of the helicopter he piloted to fight frosts in Marlborough.

"It was just luck of the draw," he said.

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"It's a hell of a hard time, because your livelihood is at stake, but having Richie there offset that a bit," Linklater said.

Richie McCaw/ Facebook All Blacks captain Richie McCaw with his Marlborough crew.

"I had no idea he was coming at all. It was a bit surreal really."

Linklater said McCaw left in the early hours of the morning. He would not say what company McCaw was flying with, but did say there was another pilot in the helicopter.

Te Whare Ra co-owner Jason Flowerday, who used the same company as Linklater, had also met McCaw, said the frost-fighting effort was a bit like rugby.

"It's great that Richie came up and did what he did, but there's a lot of good pilots up there saving the crops," he said.

"It's a team effort."

This was the first time the company had used helicopters in the past 12 years and Flowerday said he was glad they did.

McCaw had also been spotted at the Blenheim Speight's Ale House last night.

FROST FIGHTING

Climate Consulting climatologist Stu Powell said the light frost had not been as bad as one last week, but that did not stop wine companies deploying scores of helicopters, with up to 40 spotted in the Wairau Valley.

Cloudy Bay viticulturist Jim White said he had seen about 30 helicopters flying in the valley, which he thought might have been because of the damage vineyards sustained last week.

The Cloudy Bay vineyards, in the Wairau Valley, were protected by six helicopters, twice as many as the previous frost-fighting effort, White said.

There had been a heavy ground frost, so White would not be surprised if there was some damage, but at this point it was too early to tell, he said.