You will need at least 1 document to support your identity
Documents to support your identity must be valid, must be issued by a federal, provincial/territorial/state or municipal authority, and must include the bearer's name and signature.
Provincial/territorial/state driver's licence
Provincial health care card
Certificate of Indian Status
Valid Canadian passport or Canadian passport expired for a period of less than one year
United States (USA) permanent resident card
Old Age Security card
Other federal, provincial/territorial/state or municipal identification card
Federal, provincial/territorial/state or municipal employee identification card
According to the website a SIN card is acceptable for proof, as it has your name and signature. If in doubt call them and ask for the info, that way you will have the correct information.
Have you contacted your Provincial Health to see when a replacement card will be sent to you?