Fiji Council of Trade Unions (FCTU) general secretary Felix Anthony has told Radio Australia's Pacific Beat the interim government appears to not want any opposition at the elections scheduled for 2014.
"Clearly what we see now is the regime is hell-bent on ensuring it remains in power at any cost," he said.
Trade union officials in Fiji have been banned from political parties, in a move the International Trade Union Confederation (ITUC) says is "an affront to democratic principles".
Mr Anthony says the FCTU is still planning to set up a political party in defiance of the coup installed military government's rules.
He says he expects one or two party members will be arrested but that this will mean "a new start to the struggle".
"Make no mistake, by putting a few people in jail it will not mean the end of the fight," he said.
The Australian Workers Union this week passed a resolution in support of trade union and political rights in Fiji, something Mr Anthony has welcomed.
Australian Foreign Minister Bob Carr has described the conditions imposed on Fiji's political parties as "onerous" and unjustified, saying they threaten to undermine confidence in next year's elections.
The Fiji interim government declined to respond to his comments.