Germany and France want to introduce a "snap-back" mechanism suspending EU visa-free travel benefits in case of abuses of the system or migration surges, floating the idea on Thursday amid a growing debate about lifting visa requirements for Turkey.
Last month, the European Union struck a deal with Ankara under which migrants reaching Greece from Turkey can be sent back, in return for a range of concessions.
Among other things, Brussels has offered the prospect of lifting visa requirements for Turkish citizens visiting the bloc starting in July, if Ankara meets predefined benchmarks.
But the move is controversial among EU member states.
There are concerns that it could encourage people to illegally resettle in the EU or pave the way for thousands of Turkish Kurds to seek asylum in the bloc. There are also worries it could create a security risk by opening the door to radicalized Islamists.
Provisions already exist to suspend visa-free travel arrangements in case of a substantial and sudden increase in arrivals. But they are too slow, taking at least nine months, according to a joint paper that France and Germany shared Thursday with other member states.
"The current migration and refugee trends make it necessary to have an efficient mechanism in place to suspend visa liberalization," says the proposal, seen by dpa.
The paper envisages a snap-back mechanism that could be triggered by: a substantial increase in people from the partner country illegally staying in an EU state; a surge in requests for asylum or residence permits; or an inability to return people to the country under agreed readmission procedures.
Under these conditions, visa-free travel would be suspended for six months.
While the paper does not explicitly mention Turkey, such scenarios have been cited as reasons for caution over the removal of visa requirements for that country's citizens.
Ratcheting up provisions to suspend visa-free travel would be a "very important tool to give people confidence" in relation to Turkey, EU lawmaker Manfred Weber of the centre-right European People's Party said Thursday.
The Franco-German proposal comes ahead of a European Commission report, due Wednesday, on Ankara's progress in fulfilling the EU's 72 conditions for visa liberalization. The EU's executive is expected to recommend the move on Wednesday if it finds that all have been met.
It would then be up to EU member states and the European Parliament to take a decision.
Turkey, which is also a candidate for EU membership, says it has already implemented most measures and will complete the outstanding ones by Wednesday.
Ankara has repeatedly stressed that its cooperation in stemming migration flows hinges on the lifting of visa requirements for short-term visits to the EU, insisting that there can be no restrictions.