The Foreign Affairs Department has warned Australians they should reconsider travel to Fiji because of the possibility of a military coup.
The Federal Government has urged Fijian military commander Frank Bainimarama not to stage a coup.
Now reports from Fiji say more than 1,000 army reservists have been called up.
Commodore Bainimarama has said he intends to "clean up" the Government if it does not drop all investigations into his officers.
Asked if the army call-up was related to this, he said "exactly".
Commodore Bainimarama told fijilive.com that if Prime Minister Laisenia Qarase did not bow to the military's demands to drop all investigations into its officers, the army would act.
"My intention of removing this Government is clear," he said.
"If they are going to prosecute me if my clean-up campaign fails, then it is their concern."
Australian Foreign Minister Alexander Downer said last Thursday "there is clear evidence he is planning a coup in the next couple of weeks".
The Foreign Affairs Department has increased its travel warning for Fiji, saying the security situation is increasingly volatile.
Previously, it warned Australians to reconsider plans to travel to the capital, Suva, but now it advises there is a high risk everywhere in Fiji.
Three navy ships are on stand-by in the region if Australians need to be evacuated.