The future chairman of the Eurogroup, the influential committee of euro zone finance ministers, has to be an acting finance minister, a German government spokeswoman said on Wednesday.

"The statues of the rules of the Eurogroup envisage that it has to be an acting finance minister," a spokeswoman for the German finance ministry said in a regular news conference.

Luxembourg's Prime Minister Jean-Claude Juncker said on Monday he would step down as Eurogroup chief at the end of this year or early next, giving policymakers just four weeks to find a successor to fill a potential power vacuum.

He had been both finance minister and prime minister when he was originally appointed.

(Reporting by Berlin bureau)