Measures will have to be taken to protect Ireland's welfare system from abuse following the enlargement of the EU in May, the Taoiseach has said.
Speaking this evening after Britain announced restrictions on migrants from the 10 accession states, Mr Ahern said: "We must protect ourselves from what could be an abuse of the system.
"That was always our position. In the last few months, the issue has become more highlighted."
Ireland today effectively became the only EU state to allow the citizens of accession countries free access to its labour market after Britain's home secretary Mr David Blunkett announced the new regime.
Britain moved closer in line with most EU countries who have put up barriers to migrants from the new member states, slapping a two-year ban on benefit claims today and introducing a worker registration scheme.
But with virtually full employment and hundreds of thousands of job vacancies to be filled, Britain would be unlikely to discourage migrant workers from coming, officials said.
Social and Family Affairs Minister Ms Mary Couglan said: "I note the reforms announced by the Home Secretary.
"I have previously been in touch with the British government about this issue and have discussed same.
"I will be examining the implications of today's British government decision and further discussions will be taking place with my cabinet colleagues in due course."
Britain and Ireland had stood alone in Europe with a pledge of no restrictions on immigration from the 10 mostly ex-communist countries that join the 15-member bloc on May 1st.
But London said the new EU citizens would be sent home if they were unable to pay for themselves at the outset.
"For two years, and possibly longer, we will require accession nationals to be able to support themselves," Home Secretary Mr David Blunkett told parliament.
"If they are unable to do so, they will lose any right of residence and will have to return to their country."
Even if migrants are deported, however, they can return the next day under freedom of movement legislation, officials added.
The measures follow scare stories in Britain's right-wing press warning that thousands of poor migrants will pour in after May 1st, overloading Britain's welfare system and stretching its already creaking public services to breaking point.
Additional reporting: Reuters