The Commonwealth has suspended Fiji's membership in protest at its recent military coup.
Cmdr Bainimarama seized power in a bloodless coup on Tuesday
The decision followed a meeting of foreign ministers from Commonwealth countries in London.
The coup, in which military chief Cmdr Bainimarama ousted PM Laisenia Qarase, has already been condemned by the UK, Australia and New Zealand.
It has also failed to win the backing of Fiji's influential Council of Chiefs and religious groups.
This is the third time that Fiji has been suspended from the Commonwealth following coups.
Commonwealth Secretary General Don McKinnon announced the suspension after an emergency meeting of the Commonwealth's Ministerial Action Group.
FIJI TENSIONS TIMELINE
2000: Brief coup put down by army chief Bainimarama
July 2005: Bainimarama warns he will topple government if it pardons jailed coup plotters
May 2006: PM Laisenia Qarase wins re-election
31 Oct: Qarase tries - and fails - to replace Bainimarama
November: Qarase says he will change law offering clemency to coup plotters - Bainimarama warns of coup
5 Dec: Military declares coup
"Fiji's military regime should forthwith be suspended from the Councils of the Commonwealth pending the restoration of democracy and the rule of law in that country," he said in a statement.
The group "unequivocally condemned" the military take-over, calling it "a serious violation of the Commonwealth's fundamental principles".
The move means Fiji's military leaders are barred from all inter-governmental Commonwealth meetings. Existing technical assistance will continue, but there will be no new initiatives.
But Mr McKinnon said dialogue with Fiji's new leaders was important.
"It would be our endeavour to obviously engage with the regime as soon as we can in order to do what we can to bring the country back to democracy," he said.
Cmdr Bainimarama seized power on Tuesday, after a long-standing dispute with the country's democratically-elected leaders.
It was in the Pacific island nation's fourth military coup in 19 years.
Cmdr Bainimarama had accused the government of corruption and opposed Prime Minister Qarase's plan to offer amnesties to some of those involved in the racially-motivated coup in 2000.
But key groups have failed to back the take-over.
It has angered the Great Council of Chiefs, a hugely influential body with the power to appoint the president and vice-president, on the advice of the government.
The Associated Press news agency reported that the council would convene a meeting within the next few days to decide on its reaction to the coup.
Fiji's Council of Churches - another key body in Fijian society - has described the coup as the "manifestation of darkness and evil in society".
Mr Qarase, who has been ordered to his home on a remote Fijian island, has warned that public anger over the military takeover could force the new rulers to step down.
The ousted prime minister has pledged a peaceful campaign to restore civilian rule.
"There is only one legal authority in the country at this time and that is the democratically-elected government which I lead," he told local radio.