The Internet was supposed to help bring people closer together. But that's not quite the case, says a new study.

High Internet use has led to less time with family and friends and more hours working, said researchers from the Stanford Institute for the Quantitative Study of Society (SIQSS).

Researchers studied the social consequences of the Internet based on a sample of 4,113 adults in 2,689 households. They included both net users and non-users.

As Internet use grew, respondents reported they spent less time with real people, and more time working for their employers at home — without cutting back their hours in the office.

Professor Norman Nie, director of SIQSS, is disturbed about the growing isolation caused by Internet use. "This is an early trend that, as a society, we really need to monitor carefully," he said.

Those who spent fewer than five hours a week on the Internet — about two-thirds of those surveyed — did not report large changes in their daily behavior, researchers said.

But the other 36 per cent who used it five or more hours a week reported significant changes in their lives. The largest changes came from those who spent more than 10 hours a week on the net — currently only 15 per cent of all users but likely to be a larger number in the future.

"The Internet could be the ultimate isolating technology that further reduces our participation in communities even more than did automobiles and television before it," Nie said.

The study also showed that time spent in cyberspace grows with the number of years a person has been connected.

Researchers emphasized that their analysis is preliminary. SIQSS plans to conduct follow-up studies.