Fiji police say it's in the country's best interests to move to charge the commander because of his ongoing threats to the government.
The police commissioner, Andrew Hughes, says Commodore Frank Bainimarama might be arrested on charges of sedition, which is punishable with seven years imprisonment.
Mr Hughes says the police are also gathering evidence in a bid to eventually charge the commander with treason.
Mr Hughes says the commander's latest threats to force the government to resign are potentially seditious, given the army's access to firearms.
He says the police won't arrest him immediately, because he's likely to be jetlagged.
But, he says, the aim is to charge him as soon as possible after he returns from the Middle East on Tuesday.
"These are relatively straight forward matters and so we can proceed quickly because we believe it's in the best interest that some positive action is taken because there is an ongoing course of conduct by the commander which is unsettling."
Mr Hughes says its likely the commander will be invited to an interview and it'll be up to him to decide if he wants to co-operate.
He says the police probably have enough to proceed without an interview.