The product is called the Fisher Price Newborn Rock 'N Play Sleeper, and has been sold in Canada since March 2011.
The model number is R6070; that is the only model of this product sold in Canada.
Health Canada says mould can develop between the removable seat cover and the hard plastic frame of the sleeper.
Exposure to mould is a health hazard.
Health Canada says parents should check for mould and stop using the sleeper if they find it.
Consumers can contact Fisher Price for information on how to remove mould from the sleeper, or find care and cleaning instructions on the company's customer support website, http://service.mattel.com/us/.