THE Prime Minister, Kevin Rudd, has condemned the decision by Fiji's President, Ratu Josefa Iloilo, to abrogate the country's constitution, calling it a grave and unwelcome development and warning it could lead to the country being expelled from the regional forum of Pacific nations.

The Department of Foreign Affairs yesterday warned Australians travelling to Fiji that the latest developments would increase political uncertainty and visitors there should exercise caution.

"The current political uncertainty could lead without warning to an outbreak of violence and civil unrest," the department said in an updated travel advice for Fiji.

Mr Rudd said the Fijian Court of Appeal had clearly ruled this week that the ousting of the democratically elected Qarase government in 2006 was invalid and that the interim Bainimarama government was illegal.

He said the court had recommended elections be held promptly. 'That is the right course for Fiji and the only way forward for the people of Fiji.

"Instead, today's decision by President Iloilo - at the behest of coup leader Commodore Bainimarama - to abrogate the constitution, remove the judiciary and defer any elections until 2014 is yet another backward step."

Mr Rudd said leaders of the Pacific Islands Forum had considered suspending Fiji from the group at their annual summit in Port Moresby earlier this year.

"Today's actions can only increase the likelihood of Fiji's suspension," he said.

"Australia's commitment of friendship to the people of Fiji remains strong, but with the Fijian economy already in decline, this is a grave and unwelcome development."