The General Secretary of Fiji's Council of Trade Unions Attar Singh says there's waning interest in joining unions because of the interim regime's actions against the union movement.
Mr Singh says unionists are closely watching the trial of Trades Union Congress president Daniel Urai who's been charged with urging political violence and inciting antagonism against the interim government.
National Secretary of the TUC Felix Anthony has been held in custody since Friday.
Mr Singh says the cases make unionists feel concerned and intimidated.
"It has the effect of weakening unions, it has the effect of causing confusion as to what unions can do, what unions can't do and also of sending a general signal out there that it's best to remain out of unions because you could face consequences that you might not expect."
Attar Singh says he will be following the evidence closely when Mr Urai's case comes up.
The Suva Magistrates Court is due to deliver Daniel Urai's bail ruling tomorrow.