A lawyer for the unions seeking to stop the use of temporary foreign workers from China at a northern B.C. coal mine says the company advertised those jobs for $10 to $17 less than what is paid at a nearby mine for similar work.

Charles Gordon has told a Federal Court judge the company was also looking specifically for workers who speak Mandarin.

He says allowing the temporary workers to fill the jobs will directly affect the unions and Canadian workers, and the court should hear the unions' challenge to the permits that are allowing them to come to Canada.

However, the Crown and the mining companies say the unions have no right to challenge the temporary work permits.

Gordon says the Crown is siding with the companies and trying to silence the unions.