Support is growing at the UN for a joint bid by four influential countries to increase the number of members of the Security Council.
The four say their bid is essential for the UN's legitimacy
Germany, Brazil, India and Japan are seeking permanent seats on the council for themselves and one African nation.
France and Britain, two permanent council members, backed the move at the General Assembly - although Italy expressed its opposition.
France also restated its disapproval of the invasion of Iraq.
French Foreign Minister Michel Barnier told the meeting his country would not send troops to Iraq, despite calls from UN Secretary General Kofi Annan for protection for UN personnel there.
"As everyone knows, France did not approve of the conditions in which the conflict was unleashed," he said. "Neither today nor tomorrow will it commit itself militarily in Iraq."
Pakistani President Pervez Musharraf also ruled out sending troops.
BBC diplomatic correspondent Jonathan Marcus says UN reform is not only on the agenda of the General Assembly but in the very air, and there is a growing feeling that the UN needs to be recast.
Mr Barnier backed the four countries' bid, and said Paris was in favour of increasing the numbers of both permanent and non-permanent members of the council.
The current model of the UN Security Council dates from the end of World War II
The call was echoed by UK Foreign Secretary Jack Straw - who also voiced support for a Russian proposal to stop suspected terrorists using political asylum in other countries.
India and Germany put forward their case for the reforms of the security council, saying it was essential for the legitimacy of the UN.
"The inclusion of countries like India would be a first step in the process of making the United Nations a truly representative body," Indian Prime Minister Manmohan Singh said.
German Foreign Minister Joschka Fischer said the reasons for the reforms "speak for themselves", as they would give the UN more authority.
Senegalese President Abdoulaye Wade called for two permanent and two non-permanent African seats, while Nigerian President Olesegun Obasanjo argued that his country was well qualified for permanent membership.
But Italy voiced its opposition to the move, saying it favoured only the inclusion of more non-permanent seats on the council.
"We do not believe the council's difficulties can be
resolved through new permanent, irrevocable appointments," Foreign Minister Franco Frattini said, adding that Arab nations might feel excluded.
UN Secretary General Kofi Annan is known to favour an expansion of the council, to enable it to command greater respect - especially in the developing world - and to make it more effective.
Washington, meanwhile, has backed Japan's bid for a permanent seat, but reserves judgement on Germany, India and Brazil.
The council's five veto-wielding permanent members are the UK, China, France, Russia and the US.
The 10 other council members are chosen for two-year terms by regional groups.