The Fiji interim prime minister, Commodore Frank Bainimarama, has threatened to expel the US ambassador, Steve McGann.
Commodore Bainimarama has told FBC News says the actions of Australia, New Zealand and now the US were hindering progress in Fiji.
Australia and New Zealand have had their top diplomats sent home.
Commodore Bainimarama has told the Fiji Sun newspaper that he is open to suggestions from the public on what it thinks should be done with Mr McGann.
A Fiji-born academic at the Australia National University, Brij Lal, says removing the US ambassador could prove to be a serious error.
"It'll be the biggest mistake Fiji will make if it decides to expel the American ambassador. The US is not Australia or New Zealand - it has enormous clout globally."
It is not immediately clear why Commodore Bainimarama is now considering expelling Mr McGann.
Last week however, Fiji revealed that the US hadn't granted visas to Fiji officials, which Fiji says it will take up with the United Nations.
However, travel bans have been in place on coup supporters ever since the elected government was ousted by the military in 2006
Earlier this week, Commodore Bainamarama questioned whether Mr McGann or the US secretary of state, Hillary Clinton, was lying by saying the US was committed to re-engaging with Fiji.
The visa issue prompted Commodore Bainimarama to tell the Fiji Sun newspaper that foreign affairs officials had summoned Mr McGann last weekend to express Fiji's concern.
Hours after he made the claim, the US embassy issued a statement to say Mr McGann had already been out of Fiji for more than a week.
When contacted by Radio New Zealand International, the Fiji foreign ministry declined to elaborate on who was summoned, if anyone had been summoned at all or if the ministry had been unaware that Mr McGann was out of the country.
It referred queries to the prime minister's office which in turn said it was a matter for the foreign ministry to clarify.
The American embassy, being aware of the debate about a possible expulsion, says it will make no further comment at this stage.
The information ministry in Suva has also not commented.
Brij Lal says Fiji should try to improve ties with countries wanting to help.
He says the regime members may be misjudging their powers.
Unless they can have their way all the time, not only domestically but internationally as well, they simply throw up tantrums and threaten to expel people.
Last month, Fiji deported a US executive without saying if he had broken any law.
It simply alleged he had interfered in Fiji's domestic affairs.
