Britain will use future negotiations in Europe to pursue the Government's objective of limiting the application of the Working Time Directive in the UK, Downing Street has said.
But a spokesman declined to discuss reports that David Cameron has agreed a framework for negotiations with German Chancellor Angela Merkel, under which a review of the directive would be linked to Berlin's ambitions for treaty change to tighten the EU's fiscal rules.
Press reports suggested that a tentative deal was agreed during the Prime Minister's visit to Berlin on Friday, under which Germany would allow an examination of the impact of the directive, which limits the working week to 48 hours across Europe.
In return, Mr Cameron reportedly agreed that the UK will sign up to German proposals for a "narrow" amendment to the Lisbon Treaty to put the eurozone's fiscal rules on a legal basis and introduce automatic sanctions for any of the 17 single currency states which breach them.
Mr Cameron's official spokesman refused to reveal whether the directive was discussed when the two leaders met on Friday. He said European Council President Herman van Rompuy has been asked to prepare a paper on economic governance for the next summit of all 27 EU leaders in Brussels on December 9.
Mr van Rompuy is expected to set out a range of options for reform, which is thought likely to include the possibility of limited treaty change, as favoured by Berlin. But he has not been asked to address the issue of working time laws.
However, it is thought possible that the UK may use the opportunity presented by any treaty change proposals to press its case for reform of the directive.
Britain already has an opt-out, which allows individual workers to say that they do not wish to be limited to a 48-hour week. But European Court of Justice rulings have had an impact on particular groups, such as doctors, oil rig workers and those whose job involves being "on call" for periods of time.
The Coalition Agreement drawn up last year commits the Government to "work to limit the application of the Working Time Directive in the United Kingdom".
And Mr Cameron's spokesman said: "There are always negotiations going on in the European Union. We will approach future negotiations in a way that furthers our national interest." It was too early to say what the Government's stance would be in negotiations on Mr van Rompuy's report, as the document has not yet been received, he said.