Squadrons of helicopters are on standby throughout New Zealand as grape growers prepare to battle frosts overnight on Friday.
Up to 100 helicopters are expected in Marlborough, the biggest wine region, with below-zero temperatures forecast.
Frosts are also expected in Central Otago, Canterbury, Wairarapa and possibly Hawke's Bay.
Hovering helicopters and wind machines will be used to keep frosty air away from vulnerable vines which are at the "influorescence stage" with berries not yet formed.
Marlborough grower Stuart Smith says helicopter pilots are used to working close together over vineyards and their machines will be lit up.
