A French Polynesian union, A Tia I Mua, has threatened to block the roads of Papeete should the government refuse to abandon a local law on union representation, known as the Sommers Law.
The threat is also aimed against planned increases of social security fees and to win a 12 percent pay increase.
The union had been joined by others in early June in a poorly followed general strike called to protest against the high cost of living.
There had been massive protests against the reforms in December when the road access to Papeete was blocked.
The A Tia I Mua says it won't issue a legally required strike notice but just start blocking roads, adding that fishermen will block the port.
A similar threat has been made by sacked members of the GIP intervention force who have occupied a key building in the port, with them saying they won't accept any court ruling that could go against them.
Since last year's fall of the Gaston Flosse-led government, there have been several crippling blockades in Tahiti which were tolerated by the French authorities although they were illegal.