The figures, which predict annual advertising expenditure growth will fall from a five-year high of 22.6 per cent down to an annual growth rate of 9.8 per cent, also indicate that television will experience the most pronounced slowdown, falling from 26.5 to eight per cent.
The results show a similar trend across the region, with a pre-Olympic growth rate of 7.7 per cent dropping to 4.9 per cent after the event.
According to Zenith, the Olympics in 2008 will assist China in overtaking France to become the world's fifth-largest ad market. "While the growth won't be as impressive post-Olympics - not just in China, but across Asia-Pacific - we're still expecting it to be (strong)," said Matt Semple, regional development director, ZenithOptimedia.
"In China, CCTV is talking about franchising footage and content to about 60 stations nationally and the outdoor market is taking off. Advertisers are really looking around for three-year deals, so there's a huge demand but limited supply, especially for high-profile sites."
According to the global figures, internet spending is expected to overtake radio in 2008, a year earlier that forecast in December.
Another key forecast indicated that the gap in advertising spend between Asia-Pacific and Europe will halve to US$6.5 billion.
This will be thanks to the steady uplift in internet spend and a surge in China investment, with an average of 24 per cent growth in online far exceeding figures in other media.
The two markets which are experiencing the slowest levels of growth are Thailand and Taiwan, Semple noted.
Both countries have suffered from political uncertainty in recent times, but he pointed out that the political environment, combined with the Olympic effect, would see the markets begin to recover.
