Summit host President Olusegun Obasanjo tried to take the issue off the table by organising a six-nation working group to examine Zimbabwe's suspension and report back to the 52 leaders later in the weekend.

One of Mugabe's most determined critics, Britain's Prime Minister Tony Blair, criticised the decision, calling on the body to send Mugabe a strong signal that it would not tolerate abuses of human rights and democracy.

"I think it would have been better to deal with it straight away, but I think it's fine as long as we deal with it," Blair told reporters after the first executive session of the Commonwealth Heads of Government Meeting.

"I think it was anticipated that there would be some sort of process before we reach a final decision as obviously there are different views," he said.

"I hope and remain reasonably confident that the suspension of Zimbabwe will continue until such time as they comply with what the Commonwealth set out in terms of human rights, democracy and proper governance," Blair said.

Blair was the first to leave the first working session of the summit, by-passing a reception for leaders held by Commonwealth Secretary General Don McKinnon, to hold a 20-minute meeting with Obasanjo.

New Zealand's Prime Minister Helen Clark said she too was confident Zimbabwe would not be readmitted to the Commonwealth at the meeting, but admitted that disagreements remained over how to encourage reform.

The southern African country, which like most members of the Commonwealth is a former British colony, was suspended in March last year after Mugabe's re-election was marred by violence and fraud.

Zimbabwe has since plunged into economic crisis against a background of political repression and unrest triggered by a controversial programme to seize white-owned farms and distribute the land to blacks.

Many African nations, led by South Africa, want Zimbabwe to be brought back into the fold to encourage Mugabe to push forward with reforms, while the so called "white Commonwealth" of Britain and Australia favour a tough line.

"We don't think that isolation is the best way if you want a change in any country," President Joachim Chissano of Mozambique, the acting chairman of the African Union, told reporters in Abuja on Thursday.

For his part, Blair described Mugabe's behaviour as "totally unacceptable".

In Zimbabwe, the veteran liberation leader was in defiant form.

"Listen to what we are saying. Zimbabwe is for Zimbabweans. Let the Commonwealth also hear that Zimbabwe is for Zimbabweans," he told a rally.

Officials said that the Commonwealth panel -- made up of representatives of Australia, Canada, India, Jamaica, Mozambique and South Africa -- would report back to the summit's 40 heads of government and 12 national representatives on Sunday.

But summit delegates said the meeting's traditional two day closed-door retreat would be tense and emotive.

Obasanjo and other leaders have said, however, that they are determined not to allow the dispute to disrupt efforts to promote democratic ideals, forge a common position on global trade talks and unite against terrorism.

The leaders appeared to have resolved another potentially divisive issue; the future of the body's secretary general Don McKinnon, a New Zealander.

He was re-elected for a second four-year term as the Commonwealth's secretary general, Canada's Prime Minister Jean Chretien said.

Officials had expected him to win any vote for a second term and had thought that Sri Lanka's suprise candidate Lakshman Kadirgamar would probably withdraw his challenge.

But "it was a vote and he won," Chretien told reporters, adding only that MacKinnon's support was "not unanimous."

The diplomatic wrangling overshadowed the formal opening of the summit by Britain's Queen Elizabeth II, on her first first state visit to Nigeria since the west African giant gained independence in 1960.

"Eradicating poverty, fighting terror, bridging the digital divide and building a more peaceful world are some of the challenges this meeting will have to face," she said at a colourful opening ceremony.

"Your decisions can make a real difference to people's lives."