BERLIN (AP) — Germany's finance minister on Saturday floated the idea of a European tax on gasoline to help finance the continent's efforts to manage the migrant crisis.

The European Union has struggled to find common ground amid the influx of people seeking safety and a better life. Germany and Sweden have allowed in large numbers of refugees, while many other countries are reluctant to share the burden.

"If the funds in national budgets and the European budget aren't enough, then let's agree, for example, to raise a levy on every liter of gasoline at a certain level," German Finance Minister Wolfgang Schaeuble told the daily Sueddeutsche Zeitung.

"Why not agree this at the European level if the task is so urgent?" Schaeuble asked. "We must secure the Schengen (border-free travel zone) external border now. Solving these problems must not fail because of limited funds."

If not all EU countries are prepared to go along with the idea, he said a "coalition of the willing" could do so.

Schaeuble is a prominent member of Chancellor Angela Merkel's conservative party. A deputy party leader, Julia Kloeckner, swiftly rejected his proposal — pointing to healthy tax revenues in Germany that helped the government to a budget surplus last year.

Kloeckner, who hopes to become governor of the western state of Rhineland-Palatinate in an election in March, said she is "strictly against any tax increase."

"It is not justifiable for German commuters who rely on their cars to have to pay the bill," she said.