Smoking will be banned in Saskatchewan's private workplaces starting Sunday. ((CBC))

A sweeping ban on smoking in private workplaces in Saskatchewan begins next week, although there are plenty of loopholes.

Amendments to the province's occupational safety rules that take effect May 31 expand on the 2005 tobacco ban that made it illegal to light up in bars, restaurants, curling rinks and other indoor public places.

Smoking has long been banned in government-owned facilities, but privately owned offices, warehouses and other workplaces weren't covered.

Now, that will change.

Smoking will be prohibited in all enclosed places of employment, including offices, warehouses, vehicles and some mines. The ban doesn't include outdoor workplaces.

First Nations can pass bylaws making casinos and other buildings on reserve lands exempt from the new rules.

The province is also making an exception for some self-employed businesses, vehicles and camp living accommodations — with permission and when other people are not present.

As well, the smoking ban doesn't apply to areas of underground mines that are more than 10 metres from other workers. Some designated smoking rooms in long-term-care homes will also be exempt from the ban.

Workers who violate the ban will have the case raised with their boss or an occupational health and safety committee.

Under certain circumstances, "repeated, flagrant disregard of the ban" may result in a fine, the government said in a release.