Frank Bainimarama did not attend the meeting in Port Moresby
Regional leaders have given Fiji's military rulers until the end of 2009 to hold an election, or face sanctions from the Pacific Islands Forum.
Meeting in Papua New Guinea, the forum said the situation in Fiji was "not acceptable by international standards".
But Fiji's self-appointed leader, Frank Bainimarama, said no vote would be held until his reforms were completed, which he claimed could take 10 years.
Mr Bainimarama, an army chief, seized power in a coup in 2006.
He now serves as Fiji's prime minister, but has simultaneously also held several other ministerial portfolios.
His government has missed several deadlines to hold elections - including one agreed at the forum in 2007 - and Fiji's nearest neighbours appear to have run out of patience.
"More than two years of rule by an unelected military government, with no clear timetable for the return of constitutional government to the people, is not acceptable by international standards," the forum's statement said.
If Fiji does not declare an election date by the start of May, and hold the vote by the end of December, the forum said Fiji would be excluded from regional meetings and lose development funding.
After the forum's meeting, Australian Prime Minister Kevin Rudd told reporters: "The interim [Fijian] government has shown complete contempt for its previous commitments to hold democratic elections by March of this year.
"The ball now is very much in the court of the interim government of Fiji to see what they do."
'Five or 10 years'
Mr Bainimarama, who did not attend the forum's meeting, has long said he cannot hold elections until Fiji has made changes to its racially based electoral system.
The Fijilive news website reported Mr Bainimarama as saying on Monday: "The Electoral Act will be changed. If it takes us five years or 10 years to hold elections then so be it."
Mr Bainimarama justified his coup by accusing the elected Fijian government of corruption and saying it was pursuing racist policies against the country's ethnic Indian minority.
But since then, his actions have attracted strong criticism from around the world.
The government's treatment of the media has come under particular scrutiny, with three Australian publishers being expelled from the country in the course of a year.
Fiji Times publisher Rex Gardner was the latest journalist to be deported, arriving back in Australia on Tuesday.
His paper had been convicted of contempt of court for printing a letter criticising judges who supported the military coup.