WA will get its first 24-hour department store with Kmart revealing it will take advantage of a quirk in trading laws to open around the clock in Eaton, outside Bunbury.

The State Government said it would monitor the store when it opened at Eaton Fair Shopping Centre in November to help decide whether to further liberalise trading hours across WA.

It is understood Coles and Woolworths have flagged opening from 6am to midnight in the same centre when it completes a $100 million expansion this year.

Commerce Minister Michael Mischin said he did not have plans for general deregulation of trading hours but would not rule out further changes.

"I will watch developments in Eaton with interest and be informed by the results of that initiative," he said.

The Shire of Dardanup, which has a population of only 11,000, was granted unlimited trading in 1994 and is one of only seven shires south of the 26th parallel where it is allowed.

Chamber of Commerce and Industry chief executive Deidre Willmott yesterday called for the change to be extended across the State.

"This flexibility should be possible throughout the State so that all retailers and their customers have the same opportunities," she said.

"This highlights once again the ridiculous patchwork quilt of regulations that apply to retail trading hours across the State."

The development has reignited the trading hours and penalty rates debate, with UnionsWA claiming the development was bad news for workers.

"Retail employers want their cake and to eat it too by radically extending shop trading hours while seeking to cut weekend and after-hours pay," UnionsWA secretary Meredith Hammat said.

Kmart managing director Guy Russo said the decision to open 24/7 was based on community demand and the regulations that allowed unlimited trading.

Though the shire had only a small population, it was expected the store would attract more than 100,000 people from the greater Bunbury region.

Recruitment of 100 workers would start soon.

"We have 19 stores across Victoria, NSW and Tasmania that operate 24 hours and I'm pleased to provide the first 24-hour department store in Western Australia," Mr Russo said.

Geoff Prosser, director of the shopping centre developer Citygate Properties, said booming demand in the area was also supporting new bars, restaurants and apartments at the complex.

A spokeswoman for Coles said she was not aware of a decision being made on trading hours at the centre.

Woolworths said it would consider customer demand.