Just days after Australia lifted its ban on importing New Zealand tomatoes, Biosecurity NZ has suspended imports tomatoes from across the Tasman.
The temporary ban on Australian tomatoes coming into New Zealand was imposed after five of seven samples tested showed no residue of dimethoate, used to treat for fruit fly.
Imports were suspended last week and the Australian Quarantine and Inspection Service (AQIS) was asked to look into why that had happened, said a Biosecurity NZ spokeswoman.
She was not willing to speculate on why the tomatoes might have failed the test but until AQIS came up with another method for treatment or produced the results required by New Zealand authorities, the suspension would remain in place.
The two parties were in daily discussions, she said.
About 8 per cent of the tomatoes consumed in New Zealand come from Australia, generally during winter and early spring.
In 2007 more than 3000 tonnes of Queensland tomatoes worth A$9 million ($10.8 million) were imported.
The suspension came just days after New Zealand tomato and capsicum growers were told their produce would be allowed back into Australia under a temporary solution to cope with concerns about a pest bacteria.
Biosecurity Australia had revised its constrains on imports of New Zealand tomato and capsicum to allow shipments to resume.
New Zealand exports about 4000 tonnes of tomatoes to Australia (worth about $5m), the Pacific Islands and Japan.