Eggs from caged hens may have been falsely labelled free-range or barn-laid then sold at Perth supermarkets, producers warn.
The Commercial Egg Producers Association of WA believes substitution has been happening for the past few years, given supermarkets have been selling free-range eggs at prices lower than farming costs.
President Ian Wilson said it was starting to have a dire impact on the WA industry.
"Many of the state's commercial egg producers are struggling to remain competitive because the wholesale price demanded by supermarkets is simply unsustainable," he said on Monday.
Agriculture and food minister Alannah MacTiernan wrote to the Australian Competition and Consumer Commission with her concerns and was told an investigation was underway.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
The ACCC said it had a policy of not commenting to the media about any complaints or potential investigations.
In 2017, WA egg producer Snowdale Holdings was fined $750,000 and also ordered to pay $300,000 in court costs after it deceived shoppers by falsely labelling some of its products free-range.

