Auckland vegetable growers say prices could rise as a result of one of the driest summers on record.
The North Island city experienced its driest January since 1974 this year and has had below-average levels of rain so far in February.
Vegetable growers in Pukekohe say the lack of moisture means smaller yields, which could lead to higher prices.
They say irrigation is costly because businesses have to pay for water.
Brent Wilcox, manager of producer AS Wilcox and Sons, says the heat also attracts pests like tuber moths in potatoes.
MetService says it could be the end of the month or early March before there is any significant rainfall.