The amount of money Australians spend online is expected to swell to around $10 Billion over the next five years, prompting large and small stores to position themselves for a piece of the pie, Sydney Morning Herald reported Friday. But while the ease and security of online shopping has improved markedly in recent years, experts say consumer behaviour is still changing as people reassess what they are prepared to buy on the web. Faster parcel delivery speeds are also likely to attract more shoppers, leading to a boost in sales over the next decade. Advertisement: Story continues below This week, Australia Post cited growth in online shopping as the major driver behind its increase in annual profit, while traditional mail volumes declined. The government-owned corporation predicts online spending on its delivery services will double over the next five years, with parcel revenue tipped to reach almost $2 Billion by 2015. It comes amid heady forecasts by IBIS World, which released research showing revenue to Australian online retailers is expected to increase by 8.6 percent per year over the next five years to $10 Billion.