The authorities are worried that the thousands of Irish fans expected to descend on Wales could bring back the foot and mouth disease which can be carried by humans.

But, despite the threat to the match, it was business as usual in the Wales camp yesterday as they unveiled a side showing two changes from the team that drew 29 29 with Scotland in Murrayfield two weekends ago.

"We are aware that there is a very serious agriculture problem at the moment and we are keeping in touch with the situation. But we are preparing fully for the game to go ahead," said Wales team manager, David Pickering.

"We know the IRFU are in contact with the Irish Government with regard to the foot and mouth outbreak, but all we can do is go on normally with our preparations."

A Welsh rugby union spokesman added:"We are aware of the situation. There are very serious implications that are obviously more important than an international rugby fixture."

Stephen Jones returns at full back for Rhys Williams for the Welsh and Gareth Thomas replaces Mark Jones on the right wing.

Thomas gets the nod over twice capped Jones because of his extra experience that will see him win his 49th cap on Saturday. Stephen Jones returns after missing the Scotland game with a back muscle spasm injury that saw Williams come in at the 11th hour.

"The changes are a matter of fine tuning," said Wales coach Graham Henry.

"Stephen Jones returns at full back following a back injury and Gareth Thomas has shown good form of late and takes over from Mark Jones on the right wing.

“We have improved as a team since our first match, but this encounter will demand that we move up at least another notch."

Henry added:"This Ireland team has both individual talent and collective desire and will test us in every department."

Henry realises the significance of the fixture Wales have failed to win in Cardiff since 1983 and knows that after defeat against England and the draw in Scotland, that the Welsh nation demand victory over the resurgent Irish.

"The nature of these fixtures over the past 20 years or so defies analysis,"argued Henry.

"The sequence has to be broken and with the improvement we have shown since our championship opener, I believe this is a game we are more than capable of winning."

Wales: S Jones (Llanelli); G Thomas (Cardiff), M Taylor (Swansea), S Gibbs (Swansea), D James (Llanelli); N Jenkins (Cardiff), R Howley (Cardiff); S Quinnell (Llanelli), M Williams (Cardiff), C Charvis (Swansea); A Moore (Swansea), I Gough (Newport); D Young (Cardiff, capt), R McBryde (Llanelli), D Morris (Swansea).

Replacements: A Lewis (Cardiff), C Anthony (Swansea), C Quinnell (Cardiff) or C Stephens (Bridgend), G Lewis (Swansea), R Moon (Llanelli), A Bateman (Northampton), M Jones (Llanelli).