VANCOUVER -- More grocery store chains have implemented mandatory mask policies amid the COVID-19 pandemic.

No Frills and Real Canadian Superstore shoppers across Canada will have to mask up starting Aug. 29.

"Consistent with public health guidelines, masks are not mandatory for customers who are unable to wear one due to medical reasons," Loblaw said in a statement. "We trust our customers will respect this policy and do what they can to help keep their fellow shoppers and our store teams safe."

Whole Foods customers in B.C. are now also required to wear masks or similar face coverings when doing their shopping. The policy went into effect Tuesday. The grocery chain had previously announced in May that workers would be required to wear face masks but "requesting" customers wear masks while shopping.

Other large retail chains have implemented mandatory mask policies. As of Aug. 12, Walmart staff and shoppers across Canada are required to wear face coverings or masks while inside the stores.

In a statement to CTV News, a Walmart Canada spokesperson said more than 60 per cent of the chain's 400 Canadian stores already required face masks because of local government health orders.

With files from CTV News Vancouver Island's Adam Chan