Woolworths and Coles could face compensation payouts worth hundreds of millions of dollars under a bid to use a landmark court ruling to bolt on to an existing underpayments case new claims that they failed to ask managers if they wanted to work on public holidays.

Law firm Adero confirmed to The Australian Financial Review it plans to add the public holiday claim to its existing underpayment action against the supermarket giants when it amends its Federal Court statement of claim in the next few months.