The WA Chamber of Commerce and Industry says the bi-partisan agreement to extend trading hours to 9 o'clock on weeknights doesn't go far enough.
Yesterday, Labor leader Eric Ripper announced he had negotiated a surprise deal with the state government that will allow shops to stay open until 9pm on weeknights and most stores to open on Sundays in the metropolitan area.
But Coles and Woolworths may not be able to open on Sundays.
Under the agreement businesses that sell "durable consumer goods" will be able to open on Sundays, but there is confusion as to what this phrase means.
Chief Executive of CCI WA, James Pearson said, described the reforms relating to Sunday trading as a "dog's breakfast"
He said it would create confusion for retailers and shoppers as to what they can sell and buy on Sundays.
"Even though the decision updates our retail trading hours and gives consumers and retailers more choice, there is no good reason for WA politicians to stand in the way of Sunday trading," he said.
"Sadly, the long-running political standoff over extended shopping hours has hurt many businesses," said Mr Pearson.