Taoiseach Bertie Ahern has expressed concern that proposed measures in Britain to fight international terrorism could prevent the phasing out of controversial powers in the North.
Under the plans British police would get powers to stop and question anyone in the UK.
Anyone who refused to give their name or explain what they were doing could be charged with obstructing the police and fined up to £5,000.
Opponents compared the planned legislation being put together by home secretary John Reid to the controversial "Sus" laws of the 1970s and early 1980s.
It has been suggested that it was the Northern Ireland Office that proposed extending the provision across the UK. Stop and question powers in the North are due to be relaxed as part of the peace process but officials in the North want to retain them.
Labour chairwoman Hazel Blears told Sky News: "What I understand is that the request has come from the Northern Ireland Office because they have the powers, they want to be able to carry on using them, they find them useful."
Mr Ahern said it would be a shame if tackling al-Qaeda meant the laws were not relaxed in the North as expected.
Mr Hain said he wanted to see the details of the policy before making any judgment.