Woolworths and Coles Group said on Friday they would defend class action proceedings commenced by a law firm in Australia's federal court over the grocers' alleged misleading discount claims.

Law firm Gerard Malouf and Partners has lodged two class action suits against the supermarket giants in the Federal Court, alleging they breached Australian consumer law through misleading promotional discounts on hundreds of items. Both Coles and Woolworths on Friday told shareholders they would defend themselves against the class actions.

A consumer protection law firm has launched a class action against Coles and Woolworths, saying their allegedly misleading discount claims mean the average customer could be entitled to a refund of up to $1300.

Australian law firm Gerard Malouf & Partners on Thursday said it had filed class action lawsuits against the country's top two retailers, Woolworths and Coles , for allegedly encouraging misleading discount claims on everyday products.

Coles and Woolworths have been slugged with a new class action following allegations by the competition regulator that the supermarkets made false promises to offer best prices for cash-strapped shoppers.