The Taoiseach described as "unacceptable" a reported lapse in the measures introduced to curb the spread of foot-and-mouth disease.

Mr Ahern noted that agriculture leaders had stated that one case of the disease would ruin a £5 billion industry for a considerable period.

"Every effort, no matter how extreme it appears, must be applied."

The Fine Gael leader, Mr Michael Noonan, said two women returning to Ireland from a UK agricultural college, which was closed due to the outbreak, travelled by bus through Dun Laoghaire port.

The bus tyres were disinfected and one of the young women, from Limerick, approached the person in charge and sought advice on the regulations with which she should comply. "Details of her name and address were taken but nothing else happened. The woman was allowed to return to the family farm in Limerick . . . It appears that practice is not keeping pace with theory and the Government is making an appalling mess of this potential catastrophe."

Mr Ahern said: "What happened yesterday is not acceptable. I accept what he says at face value. Other incidents have been reported to my office this morning. I instructed that whatever is necessary must be done."

The Labour leader, Mr Ruairi Quinn, said the Taoiseach should put in place helplines, hot lines to inform people about the issue.

Mr Ahern said he had asked airports and ports to display clear signs which people would see immediately on disembarking. It should be made clear that disinfectant bays were available.