Sunday trading has been hailed a success, with claims it has helped West Australians spend an extra $322 a year - or an extra $6.20 a week.
On the eve of tomorrow's two-year anniversary of extended Sunday trading, research by the Chamber of Commerce and Industry shows the average person spent $12,550 in retail in 2013-14, compared with $12,227 in 2011-12 when shops traded six days a week.
CCI chief executive Deidre Willmott said the figures supported the chamber's calls for a further relaxation of trading hours, with 60 per cent of people surveyed wanting complete deregulation.
"The results speak for themselves," she said. "CCI's survey shows 82 per cent of West Australians have shopped on a Sunday and annual retail spending has increased $322 per person since Sunday trading was introduced.
"This has been an excellent outcome for consumers, retailers and employees."
The research shows local retail spend in 2013-14 was $32.4 billion compared with $29.8 billion in 2011-12.
The extra $2.6 billion forked out by WA shoppers - equivalent to the cost of the Elizabeth Quay development - was spent mostly on general and specialty foods, hardware, gardening and building supplies, cafes, restaurants, books, clothing and stationery.
The chamber claims inflation has had only a small impact on spending levels because retail CPI has been relatively flat. Some sectors, including clothing, have recorded negative inflation.
The Curtin Business School/CCI survey of consumer confidence found most of the 60 per cent of respondents who wanted shops to choose their own trading hours were in the 18-39 age group.
At present, only small pockets of the State allow round-the-clock trading, with Kmart at Eaton Fair Shopping Centre near Bunbury set to become the first 24/7 department store.
The survey of 400 people showed that most people (55 per cent) supported extended Sunday trading. It was particularly popular with those aged under 40. The survey also revealed support for longer Saturday trading, with 61 per cent wanting shops to open an extra four hours until 9pm.
Younger consumers were more likely to support and make use of the extra shopping time on Saturdays (62 per cent) compared with older shoppers (21 per cent).
Most (53 per cent) also wanted shops to open two hours earlier during the week, from 6am.
Rival research commissioned by the WA Independent Grocers Association showed that small retailers were struggling.
President John Cummings said big business was the winner from deregulation. He said the IGA survey, which focused on small retailers, showed almost 60 per cent suffered a fall in profits because of late weeknight and Sunday trading.
The survey found 32 per cent did not experience any change and profits rose for only 5 per cent of small retailers.
"The big national retailers will most likely grow bigger at the expense of smaller retailers," Mr Cummings said.