Major retailers including Mecca, Sephora and ASOS have been put on notice to remove illegal products from their shelves after an investigation found they were selling items containing banned microbeads.

The NSW Environment Protection Authority (EPA) identified a dozen products, including scrubs and exfoliators, from eight different companies that contain tiny plastic balls which have been prohibited from sale.

WATCH THE VIDEO ABOVE: Major retailers on notice over banned microbeads

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The microbeads — which can often be as small as a grain of sand — pose a significant environmental threat because they “are too tiny to be captured by wastewater treatment systems”.

“Once they enter the environment, they can then be taken up into the food chain,” NSW EPA investigations and compliance acting director Claire Miles told 7NEWS.

The EPA said microbeads “do not readily biodegrade and are almost impossible to remove from the environment due to their size”.

The authority introduced a ban on these types of plastics in 2022 and Miles said it is “disappointing” they were still in products up for sale, “especially by some of these larger retailers which have a huge reach”.

Mecca, Sephora and ASOS are among major retailers caught selling products containing illegal plastic microbeads that threaten waterways and the food chain. Credit: 7NEWS

The EPA has issued compliance stop notices that require these products to be removed from sale.

Retailers face hefty fines of up to $550,000 if they fail to comply, and fines of $55,000 for every day the notices are ignored.

“Microbeads do not belong in personal skincare or in our waterways and so we’re really encouraging the community to be very vigilant and check the back of the products that you’re purchasing,” Miles said.

“And if you suspect a product contains banned plastics you can report them very easily to the EPA... and we will investigate that.”