Most of the more than 250 London firms surveyed by the Confederation of British Industry said they were looking forward to the Olympics which London will host from July 27-August 12.

However, only 37 percent said they were confident about dealing with transport and logistics issues, against 46 percent who said they were nervous.

"The 2012 Games will help showcase London around the world and will be good for the economy," said Sara Parker, CBI London Director.

"But with only a month to go, the scale of the challenge is becoming clear and some businesses are still nervous about their levels of preparedness," she added.

Businesses are being urged to encourage staff to change their working hours and get more people to work from home to help ease the overcrowding on London's transport network during the Games.

There are also fears that traffic jams and road closures could disrupt deliveries, while other surveys have pointed to the risk of absenteeism during the Olympics.

The government is hoping that hosting the Games will provide a showcase for British business and help to pull the economy out of recession.

There was some good news in the survey. Almost all businesses said the Olympics and Paralympics would help to promote London internationally and more than three-quarters forecast a boost to tourism.

(Reporting by Keith Weir; Editing by Jon Loades-Carter)

• A Permanent Economic Emergency