New Caledonia's Court of Appeal has upheld last June's jailing of the leader of the USTKE union, Gerard Jodar.
The court, however, shortened his sentence from 12 months to nine months.
He was among several unionists to be convicted over the May clashes at Noumea's domestic airport when riot police battled hundreds of unionists during a strike at the local airline.
The jailing led to skirmishes in early August when union supporters were setting up blockades across many Noumea areas as part of an unsuccessful campaign to win the unionists' release from prison.
Within the next five days, the verdict can be appealed in a higher court in Paris
An USTKE leader has told local radio that the union doesn't accept the ruling, saying the unionists are in prison not for what they did but for who they are.
The union has again suspended its general strike, and suggested taking its objection to the court decision to the European Human Rights Court and the International Labour Organisation.
