CANBERRA: A major mystery campaign by the Australian government has created a shortage of television airtime after federal marketers snapped-up around A$10 million ($8m; €6m; £4m) in ad slots for the next eight weeks.

The heavy demand for airtime has prompted some industry commentators to forecast 6% advertising growth for the six months to June 30, despite a slide in audience numbers at the beginning of the year.

Primetime audiences across all demographics for the three commercial networks trio are down 6.6% for the first five weeks, while viewing numbers for people aged under 40 are down 7.6%.

Media agencies Universal McCann and Carat are still optimistic about prospects for 2007, but the GroupM alliance - part of the WPP Group conglomerate - is less bullish.

Mediacom ceo Anne Parsons, said a TV market "correction" was already under way and advertisers would be hard pushed to pay higher rates when the networks had already suffered significant audience declines this year.

Carat MD Mandy Henry said growth of 5%-6% was possible but only if advertisers gambled that a federal election would be called for October.

Data sourced from Sydney Morning Herald; additional content by WARC staff