The news case is close to the showground

Officials from the Welsh Assembly officials said that the farm was "literally across the road" from the show ground.

But Rural Affairs minister Carwyn Jones said it was too early to say if the annual event in July - which is the biggest in the agricultural calendar - would have to be called off.

A statement on the show's website published on Friday read: "Obviously we shall now have to review our plans for the show in July but before taking any decisions we shall need to explore carefully what alternatives are open to the society.

"These could include postponing the event to a later date or staging the show without livestock classes for cattle, sheep, pigs and goats.

"These are matters which we shall be considering and much will depend, of course, on the duration of the outbreak and when it will be finally brought to an end.

Mass slaughter

Meanwhile, anger is growing in the farming community over the government's planned cull of apparently healthy animals in the latest effort to the disease.

The first animals are expected to be killed on Friday morning.

It is being reported that up to one million animals could be slaughtered.

The National Farmers' Union (NFU) said it reluctantly accepted the pre-emptive cull but others are warning of direct action against the measure.

The current total of outbreaks around the UK has risen to 261.

But experts have said that they should get a better picture from Friday of how far foot and mouth disease has spread in Wales.

Sheep take three weeks to show signs of the disease

It is now three weeks since restrictions were imposed on the movement of livestock - a period which is thought to be the maximum incubation period of the virus.

Carwyn Jones has insisted that a livestock market - implicated by the Maff - should not be blamed for the spread of foot-and-mouth.

On Thursday, he insisted that Welshpool Livestock Auctions - the Powys market which it was claimed was at the centre of the mid Wales outbreak - had been "victims of misfortune".

"The passage of the disease through the market was not a reflection on them but was simply bad luck," he said.

His comments came after the assembly ordered that all animals which spent time at the mart after 19 February - and all animals which came into contact with them - are to be culled.

Carwyn Jones: Mart was unlucky

Following talks with UK Agriculture Minister Nick Brown, Mr Jones confirmed that there would be "compensation for the full value of any animal compulsorily slaughtered under these arrangements".

But Farmers' Union of Wales President Bob Parry said he wanted to see scientific justification for killing healthy animals, to ensure it was not being done for political reasons.

Meanwhile, up to ten schools in Powys will be closed as of Friday to prevent any risk of farmers' children spreading the the infection.

The NFU has set up a new dedicated helpline to answer queries on foot-and-mouth: 08000 646363.