Commonwealth leaders have decided to set up a six-nation panel to examine Zimbabwe's suspension from the grouping at their summit in Nigeria.
Absent but on everyone's mind: Robert Mugabe
Zimbabwe was suspended last year over allegations its presidential election was rigged.
Pakistan, also suspended after its 1999 coup, was told on Friday it could not return until it embraced reforms.
The gathering also re-elected New Zealand's Don McKinnon as Commonwealth secretary-general by 40 votes to 11.
Some nations angry at the former foreign minister's handling of Zimbabwe backed a rival candidate - Lakshman Kadirgamar, a former Sri Lankan foreign minister.
The meeting of 52 nations opened in the Nigerian capital Abuja on Friday with a glittering ceremony led by Queen Elizabeth.
The Zimbabwe panel members are expected to report their findings over the weekend.
A group of southern African countries want Zimbabwe readmitted to the Commonwealth.
But others, including Britain, Australia and New Zealand say that cannot happen until Zimbabwe makes progress towards meeting Commonwealth standards on democracy and human rights.
Summit host President Olusegun Obasanjo proposed that representatives from Australia, Canada, India, Jamaica, Mozambique and South Africa meet separately from the
main council to draw up their report.
Zimbabwe's President Robert Mugabe argues there is a white-led conspiracy against him and has threatened to withdraw from the group.
BBC diplomatic correspondent Barnaby Mason says the investigating committee could find itself deadlocked.
It contains two states from southern Africa, two from the predominantly white Commonwealth and two whose views are less clear, India and Jamaica.
However, top-level summit sources say Commonwealth leaders want the matter settled and mechanisms for monitoring Zimbabwe's performance are being looked at, according to our correspondent.
One possibility is that the suspension would continue for the time being, with a provision for reviewing or even lifting it if the situation improves.
Namibian sources said they believe there would be an internal settlement soon between the Zimbabwe government and opposition though there is no sign of it so far.
Some Zimbabwe supporters accuse its critics of double standards, since countries such as Australia have suggested Pakistan could be re-admitted to the organisation - though military dictatorships are not supposed to be allowed in.
But on Friday, New Zealand premier Helen Clark said the Commonwealth would not readmit Islamabad until General Musharraf had stepped down as head of the armed forces and made further moves on democratic and judicial reform.
The official agenda for the conference, held every two years, ranges from the environment to poverty to HIV and Aids.
Elections for secretary general
Official theme: Development and Democracy
The 52 leaders at the event represent almost one-third of the countries in the world, and about 1.7 billion people.
Delegates all received a special edition of the Zimbabwe Daily News, a paper which has been shut down for its opposition to Mr Mugabe.
The paper contains "details of the violence, of the murders, of the political repression that has happened to us in Zimbabwe," editor Bill Saidi told the BBC.
Mr Saidi said he hoped Zimbabwe would not pit black against white within the Commonwealth.
Mr Mugabe addressed the annual conference of his ruling Zanu-PF party in the central town of Masvingo as the Commonwealth summit opened.
He criticised the Commonwealth, adding there were "many other clubs to join".
UK Prime Minister Tony Blair had earlier said it was important to maintain Zimbabwe's suspension "because that sends the right signal of strong disapproval for what is happening in Zimbabwe at the
But the president of Malawi, Bakili Muluzi, has said the exclusion of Zimbabwe from the Commonwealth will hurt only Zimbabweans and not President Mugabe.
Secretary General McKinnon faced a challenger in Abuja
On Wednesday, Zambia's President Levy Mwanawasa announced he would lead a campaign to readmit Zimbabwe.
Mr Mugabe himself blames his country's suspension from the body of 54, largely developing, states on an "Anglo-Saxon unholy alliance" of Britain, Australia and New Zealand.