Surfing the net has become an obsession for many Americans with the majority of US adults feeling they cannot go for a week without going online and one in three giving up friends and sex for the web.

A survey asked 1,011 American adults how long they would feel OK without going on the web, to which 15 per cent said a just a day or less, 21 per cent said a couple of days and another 19 per cent said a few days.

Only a fifth of those who took part in an online survey conducted by advertising agency JWT between September 7 and 11 said they could go for a week.

"People told us how anxious, isolated and bored they felt when they are forced off line," said Ann Mack, director of trend spotting at JWT, which conducted the survey to see how technology was changing people's behaviour.

"They felt disconnected from the world, from their friends and family," she told Reuters.