Vanuatu's National Workers Union is planning legal action to enable it to stage a demonstration to promote the rights of workers.
The union has submitted three different applications to petition the government but the acting police commissioner, Lieutenant Colonel Aru Maralau, has denied all of them.
By law a permit must be granted by the police for a public demonstration.
A union spokesman, Joe Neil, says it seems as if the commissioner is acting on orders from people who do not want the mistreatment of workers to be exposed.
Mr Neil says they are determined to go ahead with the demonstration.
"We'll try all avenues then we'll see where we go from there. We're not giving up. We can try and take it to court and get the court to force the minister to give us permission. Failing that, well just bugger him, we will go anyway."
The union has more than 1,000 members and Joe Neil says the local community has also indicated a willingness to take part in any action.