The United Nations High Commissioner for Human Rights, Mrs Mary Robinson, has expressed serious concern about proposed new EU anti-terrorism laws.
And she warned that the US-led military campaign in Afghanistan risked infringing human rights if it caused undue hardship to civilians.
Speaking in the Belgian city of Ghent, Mrs Robinson said she welcomed the international community's resolve to combat terrorism and praised measures aimed at freezing terrorist assets.
But she said there was a danger that democracies would introduce measures that erode civil rights and that non-democratic countries would increase repression against dissidents.
She said she had worries about an EU proposal for a European arrest warrant that could allow suspects to be held for lengthy periods before being charged.
"There are serious concerns. I am concerned about what countries might do to extend powers of detention and what they might do in the area of pre-emptive arrest," she said.
The Minister for Justice, Mr O'Donoghue, has suggested that detention for the purposes of investigation, which is envisaged under the EU proposals, could be unconstitutional. EU ministers hope to agree the terms of the warrant by December 6th.
Mrs Robinson also expressed concern over EU proposals to change asylum procedures following last month's attacks in New York and Washington.
"They would be allowed to exclude asylum-seekers where it is believed they might possibly have been involved in terrorism.
"That means you could exclude whole nationalities."
Mrs Robinson was attending a conference on globalisation organised by Belgium's Prime Minister, Mr Guy Verhofstadt, in his role as President of the European Council.
She told the conference that international co-operation against terrorism should be matched by determination to improve human rights, including social and economic rights.
Mrs Robinson stopped short of calling outright for a halt to the bombing of Afghanistan to allow aid to reach civilians.
But she said the US should listen carefully to those who advocated a bombing pause during the Muslim holy month of Ramadan.
"It is very necessary, if possible, that there would be a pause. It's not just getting the food in, it's getting it distributed.
"And it's not just food and shelter, it's medical care. There is a very significant number of Afghan women who are pregnant and I fear to think of their situation.
"These are human rights. The civilian population of Afghanistan has a right to life.
"They should not be suffering unduly from the effects of a military strategy," she said.
Looking to the future of Afghanistan following the end of the conflict, Mrs Robinson said it was vital the international community insisted that women should participate in shaping the country's future.
She said the make-up of the 120-person special council to discuss Afghanistan's future should have a strong gender perspective.
"Are we really going to back an all-male council? More than half the population of Afghanistan are women.
"They need this kind of support now. It won't be popular with the men but I think if there's enough international support, it could happen," she said.
Mrs Robinson praised the activists who campaign against the present system of globalisation and said it was important that, during the present crisis, dissident voices should be heard.
"I'm a little worried about a tendency to characterise those who raise objections as somehow morally weak.
"It's extremely important that people have the courage to ask questions," she said.
The former US president, Mr Bill Clinton, who also addressed the conference, began his address with a tribute to Mrs Robinson and an apparent reference to IRA decommissioning.
"When she was president of Ireland, we laboured together on the Northern Ireland peace process. In a dreary world, it's a happy occasion and I thank you for everything you did," he said.
