The quality of New Zealand's most valuable vegetable export crop may be affected by the recent deluge.
Last Friday's heavy downpour washed tonnes of onions off the Pukekohe fields where they were drying, and left others lying on soggy ground.
Onion exports are worth $150 million a year and exports to New Zealand's main market, Europe, were set to ramp up this week.
Onions New Zealand chief executive James Kuperus said initial fears that volumes would be down had eased, and quality would be more of a factor.
"We're a low-volume producer in New Zealand but we target higher export values so if the onions have been sitting in the field longer than we want or if they are stained because of the soil that's a big concern for us."
It takes six to eight weeks for the onions to be transported to Europe, so any of lower quality would deteriorate further by the time the shipments arrived.
"If they don't sell when they get there we still need to pay for the shipping, so really we won't know the full impact until August, September this year," Kuperus said.
Unsafe to operate avocado harvesting ladders
The tail end of New Zealand's $150 million avocado export season has been cut short by this week's torrential rain.
Seeka grows and exports avocados grown in Bay of Plenty and Northland, and chief executive Michael Franks said it wasn't safe to operate harvesting ladders on extremely waterlogged ground.
Export volumes would be down because the window for sending fruit offshore would close before harvesting could pick up again, he said.
"We will probably miss the window to ship to Australia so the remaining fruit will go into the domestic market when we can get to it.
"I'd say about 5 percent of our export crop won't go offshore, but still the export market returns are much higher than the local market - probably double."
This was the third year in a row growers had had low returns and some would be losing money, he said.