However Sir Martin is optimistic about China, even though WPP's business there and India for the first six months of this year was tougher than a year earlier.
Sir Martin said he expected a V-shaped economic recovery in China, that is a rapid advance after a steep decline, with economists predicting China's economy to grow by around 8 per cent.
WPP revenues in China last year accounted for $950 million out of the $13.6 billion group total, with India accounting for $400 million in revenue.
In other parts of the the world, WPP clients are being cautious, Sir Martin said, and they "won't invest again until they are sure".
This week, WPP media agency GroupM, said it expects advertising spending to grow by 5.8 per cent to 254.5 billion yuan ($37.3 billion) in 2009, and by 9.8 per cent to 279.4 billion yuan in 2010.
