The rule, which will affect three million UK workers, means employees cannot work more than 48 hours a week regardless of their personal circumstances and this could have an impact on companies struggling because of the economic downturn.
It also means those working more than 48 hours currently will have to cut back their working time.
Yesterday, John Cridland, director general of the Confederation of British Industry (CBI), urged European ministers to allow staff the option to work in excess of these hours.
He said: "Some people want longer hours, some people don't. The opt-out gives them a choice.
"These amendments are misguided. In hard times, somebody may want to work extra hours to help support their family. Staff in a company that's fighting for survival may choose to work longer hours.
"We think people can look at their own circumstances and decide if they want to work longer hours. We call this common sense and it doesn't need any amending by Brussels."
It is expected a final decision from the European Parliament will be announced later this year.
