A claim that foot and mouth disease has been released on Waiheke Island is likely to be a hoax, says the New Zealand government, but it has put precautionary measures in place and informed New Zealand's trading partners.

A letter received by the Prime Ministers office on Tuesday said that the disease had been released deliberately on the island which is near the city of Auckland.

"MAF wishes to reiterate that this situation is believed to be a hoax, but must be taken seriously," the Ministry of Agriculture and Forestry said today (Wednesday). "Anyone with information on the claimed release should contact their local police station. Given the resources that must be deployed, both MAF and Police are appealing for anyone with information to come forward immediately."

Precautionary measures have been put in place. "Farmers and vets are asked to be vigilant and keep a close eye on their cattle for signs of disease," the ministry said said.

"MAF still regards New Zealand as foot and mouth disease free," it said.

"Overnight, over 50 trading partners, including major member countries of the EU, have been informed of the situation," the ministry said. "Most have expressed appreciation at the early advice, confidence in New Zealand's management of the situation, and a desire to be kept informed. Our major trading partners (US, Canada and the EU) have offered assistance."

"The World Animal Health Organisation (OIE) has also been informed and MAF is working with the farming industry to address their concerns," it said.

At 5pm on Tuesday a  controlled Area notice for Waiheke Island became effective. "There are currently six veterinarians, two specialist exotic disease investigators and three media liaison staff working on the island," the  ministry said. "Checkpoints have been established at the two main ferry terminals on the island and nine police officers are present to support MAF staff. Efforts are focusing on the 12 largest properties, as these hold the greatest numbers of stock and pose the greatest risk of spread."

Last night MAF officials were able to contact 18 of the 39 farmers on Waiheke Island.

MAF vets will today be making appointments with Waiheke farmers to observe livestock for possible signs of Foot and Mouth Disease. All stock will be checked every 48 hours for 14 days - the longest possible incubation period for Foot and Mouth Disease before clinical symptoms appear.

Pigs are by far the greatest risk of spread, but there few pigs on Waiheke Island. Cattle and sheep are a much lesser risk - there are some 2,500 cattle and 18,000 sheep on the island.

Foot and Mouth Disease is an unwanted organism under the Biosecurity Act 1993. Anyone convicted of spreading it faces a penalty of up to five years' imprisonment or a fine up to NZ$100,000 (US$73,000).

Under the Crimes Act anyone convicted of threatening to commit a crime that would cause major damage to the economy can be sentenced to seven years jail, the ministry said.  Section 298A stipulates that anyone causing disease or sickness to animals can be sentenced to up to ten years in jail.