Workers at Iamgold Corp's (IMG.TO: Quote) gold mine in Suriname, one of the Canadian company's largest, have begun a strike to protest work schedules, a union leader said on Tuesday.

Workers at the Rosebel mine, which last year produced 395,000 ounces of gold, walked off the job at midnight on Monday, union activist Freddy Brug told Reuters.

Company officials were not immediately available to comment on whether operations have been affected.

Brug said miners were opposed to management's efforts to introduce a 16-hour shift. He did not say what proportion of the workers were on strike.

Iamgold, a mid-tier mining company, plans to produce roughly 1 million ounces of gold this year and 1.8 million ounces annually within five years.