That's in addition to 300 spaces he announced last week.
Prentice says one of his priorities is to provide seniors with safe, affordable and quality housing that is close to their families and friends.
The project has been put out to tender and the deadline for applications is Dec. 19.
Prentice says priority will be given to bids from companies that can begin development within six months.
The cost is pegged at $180 million, which the government hopes to share 50-50 with the private sector.
Supportive living is designed for people who are no longer able to stay in their own homes. Residents have private rooms and have access to meals, housekeeping and 24-7 professional nursing care as required.
(CHQR, The Canadian Press)