The internet will be the biggest advertising medium sooner than expected according to the country's biggest media buyer, Harold Mitchell.

In The Newsport article "Mobile technology a boon for advertisers" (5 August), the Interactive Advertising Bureau (IAB) predicted the internet would take the lead as the preferred avenue for advertisers in four years, but Mr Mitchell believes it will be closer to three years if the National Broadband Network (NBN) goes ahead.

"By 2013 the internet will attract 25 per cent of all ad dollars and both free-to-air TV (worth $3.2b in 2009) and newspapers will have come down to the same level," he said.

Australia has just reached the $2 billion mark for internet advertising, an increase of 13% in the 2010 financial year.

But Mr Mitchell warned that should the NBN be scrapped and other technologies be introduced, which is the plan under a Coalition government, the industry would be "set back a decade."

"…If you don't continue with the NBN as outlined and have an aggressive broadband policy, we won't reach (the expected growth levels)," he said.

Ed Smith, commercial and content director at News Digital Media (a section of News Limited), said the emergence of devices such as the iPad and other tablet style devices will have a big impact on advertisers.

"I reckon there could be half a million iPads sold by June next year," he said.

"Go forward another year and there may well be 2 million of these tablets. If these yield even $100 per person in advertising, that's $50m in a year."