European countries in the visa-free Schengen area may be allowed to restore border controls for up to a year under "exceptional circumstances" in proposals to be put to ministers this week.
A draft working document to be discussed by interior ministers in Luxembourg on Thursday followed demands from France and Germany which specifically mentioned illegal immigration problems as one reason to reintroduce checks.
But the document seen by AFP does not spell this out, and the EU's home affairs commissioner Cecilia Malmstroem has said Schengen was not designed to control migration.
She also noted that since a joint letter from France and Germany was put to ministers in April, the French government has changed following the election of socialist President Francois Hollande in place of conservative Nicolas Sarkozy.
"For us, this letter no longer exists," Malmstroem told AFP.
"I've not yet discussed it with the new French government but I'm sure France will have a constructive approach at the next interior ministers' meeting."
The draft rules if adopted would allow a state within the Schengen area to reimpose border controls for six months, renewable for another six when "exceptional circumstances" require it.
But a negotiator said ministers would have to reach common agreement, while the role of the European Commission in deciding if the circumstances were met still had to be worked out.
Sarkozy, chasing the far-right vote, in April threatened to pull out of the 26-nation Schengen zone within a year failing improved action to keep out illegal immigrants.
But the tough talk from Paris irked some of France's partners, with Belgian Interior Minister Joelle Milquet charging that "electoral concerns are playing a bigger role than the issues."
Europe has been working on ways to maintain the Schengen treaty while addressing growing Europe-wide concerns on illegal migration since last year's Arab Spring revolts threw thousands across the Mediterranean into Italy and Greece.
As a result, France temporarily closed its border with Italy.
Currently, the Schengen treaty allows renewal of border controls in the case of a terror or security threat for sports or other events.
The European Commission has previously proposed states be enabled to close borders for five days in case of migratory pressure, but must ask permission from Brussels for longer periods.