Construction has begun on a new hospital in Saskatchewan that will provide mental-health services, but questions are being raised about the cost.

The Saskatchewan Hospital in North Battleford will have 188 beds for patients in the general population and a 96-room secure unit for offenders with mental-health problems.

Health Minister Dustin Duncan says the new facility will help ensure that mental-health patients have access to timely and appropriate treatment.

The hospital is being built through a public-private partnership for $407 million and the province says that includes the cost of keeping the facility in like-new condition for 30 years.

But the Opposition NDP says the price is outrageous because $185 million is to handle maintenance of the facility.

New Democrat Danielle Chartier says that amounts to more than $6 million every -- more than the Prairie North Health Region spent to maintain all hospitals and facilities last year.

Construction of the new hospital is expected to be complete by spring 2018.

Mental-health experts have long called on the Saskatchewan government to replace the century-old psychiatric hospital, which they said could not meet modern needs for care.

The Canadian Mental Health Association's division in Saskatchewan said in 2011 that the old hospital was decrepit and run down.

David Nelson, executive director for Saskatchewan, said at the time that the old dormitory-style layout devoid of single rooms or private bathrooms left little opportunity for privacy. Nelson also said one nurse was going downstairs for an urgent issue and his foot went right through the floor on stairs.

Relatives of patients say the new facility is "a dream come true."

"It is going to be a significant improvement in all aspects of patient life. Today gives all of us -- patients, families, staff, community and the health region -- a real sense of excitement and belief in what's planned for this site and the mental-health care to be delivered here," Celeste Bridgeman, chairwoman of the Saskatchewan Hospital North Battleford Family Council, said in a news release Monday.