The global number of Wi-Fi hotspot users will more than triple this year to more than 30 million - up from 9.3 million users in 2003, according to Gartner.

By the end of 2004, more than 50 per cent of professional notebooks will have wireless local area network (Lan) capability, Gartner estimates, leading to employees increasingly using wireless Lan in the office, at home and at hotspot locations.

But the analyst warned that if organisations fail to negotiate contracts with service providers to allow access to hotspots, employees are likely to use them and list the cost under other expenses.

"Enterprises must begin tracking hotspot expenses immediately," added Phil Redman, research vice president at Gartner.

Long-term contracts should also be avoided, the analyst advised.

"Build a strategy for use of hotspots by employees, but beware of entering into subscription contracts with service providers that cannot supply roaming agreements to meet the enterprise's needs," said Ian Keene, research vice president at Gartner, in a statement.

"Organisations should avoid long-term contracts because this service sector is changing. Be prepared to supplement subscription contracts with pay-as-you-go hotspot access.

"Companies should also put in place a mechanism to monitor hotspot usage so that the company will know what to contract for when the market matures further."

This hotspot strategy should, according to Gartner, include the use of personal firewalls and secure virtual private network logins for all remote access.

The analyst group's research indicated that, if managed properly, an organisation can derive real benefits from implementing a wireless Lan strategy.

By the end of 2004 it expects travelling knowledge-based workers to be able to gain 30 minutes a day in productivity from wireless hotspots.

Gartner also predicted that the increased demand for mobile access will drive enterprises to reduce the number of wired networks they use, while increasing the number of wireless networks in 2004.