"Military commanders aren't the people qualified to run a country"
Alexander Downer, Australian foreign minister
"They really need to get over coups and embrace democratic institutions," he said. "Coups are becoming a habit there and they're doing their country so much damage."
Peters said Fiji could easily call for fresh elections "within a matter of months".
"[The] problem is basically the commander returning to his barracks and realising authority does not lie with the army," he said.
The foreign ministers said most South Pacific nations wanted to see Fiji make a rapid return to democracy.
Downer added that "military commanders aren't the people qualified to run a country".
"It seems to me his job is to defend the country from foreign invasion ... his job is not to be a politician ... or prime minister," he said.
Fiji saw its fourth coup in 20 years when Commodore Frank Bainimarama, the military chief, ousted the democratically-elected government of Laisenia Qarase on December 5 last year.
Bainimarama sacked the government, closed Fiji's parliament, sacked a raft of top civil servants, imposed a state of emergency that remains in place and named himself president.
He has since relinquished the role of president but taken the post of prime minister.
Australia and New Zealand imposed sanctions on Fiji following the coup, including travel bans on coup participants.
Peters said the measures have been taken "to see a quick return to democracy" and not to punish Fijians.
But Downer said it was unrealistic to expect the ousted civilian government to return to power.
Foreign ministers of the Pacific Islands Forum, the South Pacific region's 16-member bloc, will discuss a report on Fiji by a four-member eminent persons group in Vanuatu on March 16.
The eminent persons group had said the coup was "unconstitutional and unacceptable".