Online video services such as YouTube and Joost are pushing internet capacity to breaking point, a top Google executive has warned.

Vincent Dureau, head of TV technology at Google, said that the web will soon struggle to meet rising demand for high-quality online video.

The search giant paid $1.65bn for YouTube last year.

Speaking at the Cable Europe Conference in Amsterdam this week, Dureau said: "The web infrastructure, even Google's [infrastructure], does not scale. It is not going to offer the quality of service that consumers expect."

Google is already investing heavily just to keep data flowing, according to Dureau.

Meanwhile, a report from analysts at Deloitte predicts that 2007 may see the internet approach capacity.

The Predictions 2007 report cites increased demand for online video, but also blames social networking sites like MySpace and Bebo for " pushing bandwidth to breaking point".

A fast-growing appetite for online video is borne out by the numbers. On Tuesday more than a million people watched The Sun's online clip of a 'friendly fire' incident in Iraq, and viewing figures of up to 100 million have been linked to Loose Change, a controversial online documentary about 9/11.

UK technology researcher CacheLogic claimed that 60 per cent of the internet's peer-to-peer traffic is now video, and that the average file size is 1GB.

Online video service bosses are confident that the internet can handle the demands. Fredrik de Wahl, of recently-launched web TV portal Joost, suggested that infrastructure providers have made great strides to expand network capacity.

US infrastructure provider VeriSign, for example, is investing $100m (£51m) over the next three years to increase bandwidth by a factor of 10.

European network firm Interoute has spent €22m (£14.6m) upgrading its network to cope with demand for online high-definition video.

Tim Sparke, chief executive at Loose Change distributor Mercury Media, told vnunet.com that market forces would help solve any difficulties.

"If space needs to be rationed, then it will be rationed on price," he said. "If at peak time consumers have to pay more to access material through their ISP, they will end up downloading content outside peak times."