The EU has been threatening to suspend Turkey's accession talks, started just over a year ago, over its failure to open its harbours and ports to craft from Cyprus.
Last week, the European Commission recommended slowing down Turkey's accession process by freezing eight of the 35 negotiating chapters that EU candidates have to complete to join.
Turkey's candidacy has divided the 25 EU countries, and their ambassadors are seeking to find a common position for foreign ministers to endorse at a meeting in Brussels on Monday.
Failing that, EU leaders will take up the issue at a summit in a week's time.
Turkey's EU membership talks will take at least a decade to complete and Ankara has not guaranteed whether it will be allowed to join.
Last week, a French source said German Chancellor Angela Merkel and Jacques Chirac, the French president, wanted a "rendezvous clause" that would effectively set a deadline for Turkey to comply with EU demands.
The source said: "The idea is to have a formal review ... so at a given moment we can see if Turkey has changed and whether we can take back that decision or ... toughen it."
Afterwards, Olli Rehn, the EU enlargement commissioner, appealed to Merkel and Chirac not to press for a new deadline.
He said strict deadlines did not produce results and the Cyprus question was best solved by the UN.