Australians bought 2.3 million tablet computers in the first half of the year - almost the same number as in the whole of 2012.

More than seven million Australians are now tablet users, according to data released by research company Telsyte.

"It's remarkable that in six months we've almost bought as much as the whole of last year," said analyst Foad Fadaghi.

The figures suggest "exponential" movement away from PCs and laptops and towards tablets, he said.

"It's not a trend, it's actually a step-change - a wholesale change where people are shifting their computing habits from one platform to another."

Mr Fadaghi said customers were particularly drawn to touchscreens and the functionality allowed by hundreds of thousands of apps.

Tech companies are increasingly ploughing money into marketing their tablets and most now have a firm tablet strategy.

Telsyte's figures showed Apple is the main player. Its iPad range, driven by the iPad mini, has claimed 52 per cent of sales so far this year.

Android tablets, such as Google's Nexus range and Samsung's Galaxy Note models, were second, claiming 43 per cent.

However, current trends suggest Android tablets will outsell iPads in Australia by 2015, Telsyte said.

That would echo the current situation in smartphones, where Android is already ahead.

Microsoft trailed a long way behind. Just five per cent of tablets sold this year run its Windows operating system.

But Mr Fadaghi predicted Microsoft would make a comeback in the next few years as users - particularly business people - looked to replace their PCs. Instead of buying another PC, they would likely look to a Windows tablet.

He estimated a fifth of all tablets sold in 2017 will run Windows.

That could be even higher if the acquisition of phone maker Nokia, announced on Tuesday, improves Microsoft's hardware.

The research found larger tablet models, such as the regular iPad and Google's Nexus 10, remained the number one sellers.

But demand for smaller tablets with screens measuring 7-8 inches is growing, partly because they're cheaper.

Australians are also now buying their second or third tablet and looking for smaller and more portable models, while they use their larger tablets at home.

Wearable computers, like the "smartwatches" pundits are predicting Apple and Samsung to reveal in the near future, are unlikely to threaten tablet sales, Mr Fadaghi said.

They were "app accessories" that will compliment rather than replace smartphones and tablets.