"No outbreak of this disease has been detected here. Thai pig farms have generally adopted a standardised farming system, and exporting live pigs to Cambodia requires prior approval to move them and disease-free certification from the Livestock Development Department," said department chief Preecha Somboonprasert.

Mr Preecha made the remarks after reports emerged that Cambodia had banned pig imports from neighbours Vietnam and Thailand after animals infected with blue-ear disease were smuggled into the country from Viet Nam, infecting other pigs.

Bangkok Post reports that the ban was announced on Wednesday by Prime Minister Hun Sen, who also asked market vendors to keep pork prices stable.

"I would like to appeal to provincial authorities, especially provinces near the borders of Viet Nam and Thailand, to suspend pig imports," he said, warning that the disease could spread rapidly through the pig population.

Cambodian Agriculture Minister Chan Sarun said the outbreak followed an order by Hanoi instructing farmers in Vietnam to slaughter infected pigs.

But he said some farmers had instead dumped their pigs across the border in Cambodia at knock-down prices, spreading the disease, which is also known as porcine reproductive and respiratory syndrome.

Testing has revealed hundreds of pigs have died from the disease in four provinces bordering Vietnam, and experts said blue-ear had probably spread to half of Cambodia's 24 provinces.

In 2007, Cambodia banned pig imports from Thailand and Viet Nam for eight months after a similar outbreak.

The Livestock Development Department said Thailand exported 200,000 live pigs to Cambodia last year worth 12 billion baht. In the first half of this year, exports topped 80,000 pigs worth of 6,000 baht apiece.

Nopporn Vayuchote, executive vice-president of the Betagro Group, said the disease was not transmittable to humans.