Fiji police say they might arrest the military commander on charges of sedition which is punishable with seven years imprisonment.
The police commissioner, Andrew Hughes, says the police are also gathering evidence to charge Commodore Frank Bainimarama with treason once he returns from the Middle East.
Mr Hughes says the commander's latest threats to force the government to resign are potentially seditious, given the army's access to firearms.
Police say they want to interview Commodore Bainimarama over his public comments.
A police spokesperson says if he fails to co-operate he may get a court summons.
Mr Hughes says while arresting Commodore Bainimarama would be risky, the police don't fear a major backlash from the military.
"I'm not fearful, we're mindful, and this needs to be managed carefully obviously, and that's what we intend to do. And I think as I said, things like dragging him off the plane would be very provocative and inappropriate in the circumstances."
Mr Hughes says they also plan to charge the commander with disobeying a lawful order and this relates to him breaching an agreement not to make public statements without consulting the Prime Minister.
He says it's in the country's best interest to charge the commander because of his ongoing threats to the government.
And Fiji's Attorney General says the government's not behind plans for any possible arrest of the military commander.
Qoriniasi Bale says the government does not interfere with the work of the police.
If the police should decide to arrest him, that is their call. That is the work of the police. Our government does not get involved in that.