Employees of New Caledonia's Goro Nickel company have called on the French state to intervene to protect their jobs.
About 500 people marched on the high commission in Noumea after being out of work for ten days following the attacks on the Goro site by Kanaks opposed to the construction.
French police have broken up barricades at the site and made several arrests but Goro Nickel says it is not safe to buold and then run a 2 billion US dollar nickel plant.
The company's general manager, Ron Renton, himself one of the demonstrators, described the situation as shameful in a democracy.
The territory's former president and member of the French assembly, Pierre Frogier, has asked Paris to send police reinforcements to cope with the crisis.
Nearly 2,000 workers are affected by the unlimited suspension of the project.
A further 2,000 workers from the Philippines were due to arrive in the next two months.