Major retailers including Coles and Woolworths have united in a push to relax the industry’s minimum conditions by allowing employers to introduce split shifts, remove penalty rates for staff earning more than $67,000 a year and negotiate away “smokos”.

The supermarket giants, Kmart and Costco, as well as smaller chains like T2 and Barbeques Galore, have intervened to publicly back an Australian Retailers Association’s application in the Fair Work Commission to vary the general retail industry award.