People who use devices like Blackberries work an extra 15 hours a week because they constantly check e-mails, even after leaving for home.
This finding is based on a survey of 600 employees, which showed that such devices were turning people into workaholics by providing them with the ability to receive and send messages and work online, even when they were at home.
Pointing out that the working day was being extended to around 55 hours for many people, employment law firm Peninsula asked employers to ensure that their employees did not breach working time regulations.
"Bosses should encourage staff not to work from home unless necessary. Inform staff that they should limit working from home. If they are happy to work away then ensure they agree to opt out of the maximum working week and have this signed.
Limit the extent to which employees are using their devices when they choose to do so; unrested employees will be less productive during the working day.
"The recession has forced everyone to become more productive and for those with access to work at home, this is an opportunity for them to catch up or get ahead.
Employees with smartphones are able to respond a lot quicker and also get themselves prepared for the working day ahead by checking their e-mail first thing.
"Employees should be encouraged to take appropriate rest breaks if they do choose to continue working out of hours. Having a well-rested employee with a good work/life balance is a lot more useful than a tired employee that put one too many hours in the night before," Done added.