He had sought 11th hour talks with the 53-nation group made up of Britain and its former colonies in a bid to avoid expulsion, Ratu Jone Kubuabola, Fiji's foreign minister, said last Thursday.
However the two sides could not agree on a date.
Paul Reeves, the former New Zealand governor general, is now set to visit next week, Eduardo del Buey, a spokesman for the Commonwealth Secretariat, said.
Democracy 'road map'
|Fiji's economy has been hit hard by the isolation triggered by the coup [GALLO/GETTY]
Bainimarama said in July that Fiji would have a new constitution in place by 2013 ahead of election the following year as part of his "road map" for returning the country to democratic rule.
He had previously promised to hold polls by 2009, then 2012, before pushing it back to 2014.
International bodies including the UN and EU have demanded a rapid return to democracy and the 16-nation Pacific Islands Forum has already suspended Fiji's membership.
The international isolation has hit Fiji's tourism and sugar-export dependent economy hard.
But Bainimarama has defied the pressure to hold elections sooner.
Since the coup, he has imposed and expanded emergency restrictions, sent troops and police into media and government offices to gag opposition to his reform plans, and had expelled or fired journalists and judges who refused to stay silent.
Bainimarama told Fiji media this week that he would not be dictated to by external forces and Lieutenant-Colonel Neumi Leweni, a government spokesman, said on Tuesday that the deadline would not alter Fiji's plans.
"It is actually up to them whether they want to go ahead with the ultimatum or not, but as far as government is concerned, whatever is in the road map, that's it," Leweni told the Fiji Post.
Fiji will now be cut off from Commonwealth aid and banned from the 2010 Commonwealth games.
Fiji, a former British colony, has experienced four coups and a military mutiny since 1987, fuelled by tensions between indigenous Fijians and economically powerful ethnic Indians.
Bainimarama has said he wants to rewrite the constitution and electoral laws to remove what he says is racial discrimination against the Indian minority.
He has also insisted he needs time to reform the country's electoral system and root out what he calls endemic corruption.