Tomatoes cost 61 per cent more last month than a year ago, the result of cold weather and a ban on Australian exports of the fruit.
Tomatoes were priced at an average $8.29 a kilogram in October, Statistics New Zealand figures show.
Cold weather slows crop growth and limits supplies, pushing up prices. Peter Silcock, the chief executive of industry group Horticulture New Zealand, said the weather had been "colder than we'd like it to be" and some eastern regions were a bit drier than usual.
But this month fruit and vegetable prices had fallen as spring supplies came on. From a price of $12 a kg in September, tomatoes were about $7 a kg in central Wellington yesterday.
During October, tomato prices fell almost a third, with lettuce down 27 per cent and capsicum down 26 per cent.
The Statistics NZ figures also show fruit and vegetable prices rose 8.4 per cent in the past year, because of high tomato, kumara, avocado, pumpkin and broccoli prices.
In total, food prices rose just 0.3 per cent in the past year, helped by big falls in fresh milk, butter, cheese and bread.
As well as the impact of a colder October, tomato and capsicum prices were also higher than normal this winter because of the Australian-imposed pesticide ban on New Zealand-bound crops.
Red capsicums cost up to $13 a kg in Wellington compared with A$5.48 (NZ$7.02) in Australian supermarkets.
Last year, the usual winter tomato supplies from Australia were lost because of bad storms in Queensland, which drove up prices then too.
The pesticide dimethoate, used to treat tomatoes for fruit fly, was banned in Australia late last year because of "potential dietary risks". But it is a requirement to bring tomatoes into New Zealand.
New treatments are being considered for fruit fly, such as methyl bromide or irradiation, but they still need to be approved here. Public submissions closed last week.
Meanwhile, kumara prices were up 93 per cent on a year ago, after poor weather at planting and harvest, with prices in October just below their record high in early 2008.
In central Wellington, kumara was selling for about $7 a kg yesterday.
The prices last year were "particularly low" and at levels that were probably unsustainable for growers, Horticulture New Zealand said yesterday.
"A lot of consumers would not see them [prices now] as particularly expensive," Mr Silcock said.
Avocados were also much more pricey than a year ago, up 91 per cent, but prices had been unusually low last year.
LIKE A 'LOTTERY'
Fluctuating food prices are "a lottery" a Wellington restaurateur says.
"Broccoli is a classic. One year it's up and one year it's down. It's all weather-related," El Matador owner Mike Marsland said.
The rising price of some produce, such as tomatoes, could not be avoided. "Kiwis like their tomatoes, so you have to take it on the chin."
Monsoon Poon owner and Wellington Restaurant Association president Mike Egan said restaurants tried to absorb rising costs, before hitting customers in the pocket. "We try not to be a victim of prices rises. We buy in bulk, and we change our menus to suit the seasons."