WASHINGTON (AFP) - The young intelligence technician who leaked details of the vast US programme to monitor private Internet traffic on Monday dismissed claims that he was working as a Chinese agent.

"This is a predictable smear that I anticipated before going public," Edward Snowden said in an online interview hosted by the Guardian newspaper in which he was asked why he had gone to Hong Kong before making his revelations.

The 29-year-old old systems technician accused US officials of making the claim to distract from their own misconduct and accused the news media of having a knee-jerk response to allegations against "Red China".

"Ask yourself: If I were a Chinese spy, why wouldn't I have flown directly into Beijing? I could be living in a palace petting a phoenix by now," he said, arguing US agents should not monitor citizens of any country without due cause.

He admitted the NSA's Internet surveillance system did have a filter that is meant to protect US citizens from being caught up in its global data dragnet, but said this protection was technically weak and easy to bypass.

"The filter is constantly out of date, is set at what is euphemistically referred to as the 'widest allowable aperture', and can be stripped out at any time," he alleged.

"More fundamentally, the 'US Persons' protection in general is a distraction from the power and danger of this system," he argued.

"Suspicionless surveillance does not become okay simply because it's only victimising 95 per cent of the world instead of 100 per cent."