Hamilton's northern urban sprawl has clashed with Waikato's Zealong green tea enterprise which was forced to use helicopters before dawn yesterday to save the imminent harvest of more than one million plants from frost.

It was the first time in eight years of growing organic oolong tea on the outskirts of Rototuna, that Zealong had called in the choppers to prevent the unseasonal frost settling at 4am on 4 hectares of camellia tea plants at Borman Rd and on its 48ha operation at Gordonton Rd.

Three helicopters hovered over the two properties for about 3 hours, attracting some complaints about the noise and lights from residents of the new subdivision on New Borman Rd and Gordonton Rd.

Zealong spokesman Jeff Howell said the tea farm regretted the disturbance to residents and in trying to minimise the effect on the new subdivision which has crept up to Zealong's boundary in the past three years, leaves ready for harvest on up to 5000 camellias were killed because the helicopter avoided getting close to houses.

Mr Howell said Zealong staff visited householders yesterday to apologise for not warning them of the possible $10,000 chopper operation. Helicopters were on standby last night and would be again tonight, he said. "It was a near miss. It could have been a disaster," he said.

"We would like people's understanding.

"We can't avoid it. If there was an easier way we would do it." The company did carry out a mail drop in the area about 18 months ago advising helicopters would be on standby during high risk frost times just before harvest. Zealong harvests three times a year in January, March and early November.

Mr Howell said Zealong owner Vincent Chen commissioned a helicopter company three years ago after frost destroyed the farm's total March harvest.

Zealong's other options for battling frost damage were nets, irrigation and big turbo fans, Mr Howell said.

The tea leaves grew up through nets, Zealong had water use resource consents for only six months of the year during the hot months and could not get more, and turbo fans were "ugly and noisy" and reportedly attracted complaints, he said.

- © Fairfax NZ News