Britain's special representative in Iraq has called on the UN to take a leading role in the reconstruction of the country.

Sir Jeremy Greenstock said the international body should take the major responsibility of returning Iraq to self-government.

"The UN has a huge role through the transitional period, in my view. I want to see the UN fully involved, and perhaps in the lead, in the whole electoral, permanent constitution writing and choice of government process," he said.

He also backed proposals by US secretary of state Colin Powell for NATO to take over the military presence from July next year.

"I think it is quite a good idea, because I think it would be a sign of the kind of multilateral performance that the Iraqis want to see," Sir Jeremy said.

"I rather have a hankering for it coming into being in the second half of 2004."

Tony Blair's envoy is set to discuss the idea with UN secretary general Kofi Annan in New York on Monday.

The UN currently does not have a presence in Iraq following the bombing of its headquarters in Baghdad in August which killed senior envoy Sergio Vieira de Mello.

Iraq's post-war security has become the dominant issue but Sir Jeremy warned it would be two years before there would be any signs of stability.

"I haven't got a message of comfort for the British public, supporting or not supporting what we are doing in Iraq, in terms of massive improvements in security or the conditions of life in Iraq during 2004," he said.