Angela Merkel has taken a step towards forming a cross-party coalition and ending months of political deadlock.
Germany's Social Democrats voted to enter coalition talks with Chancellor Merkel's Christian Democratic Union party on Sunday - reversing an earlier decision.
Social Democrat leader Martin Schulz urged the party to vote in favour after winning a number of concessions from the CDU.
Any coalition agreement still needs to be approved by the Social Democrat membership, who will vote on the matter later.
If that fails then Mrs Merkel's only options are to form a minority government or seek new elections.
Elections last September confirmed Mrs Merkel's position as Chancellor for a fourth term.
But her party only gained 33% of the votes, down from 41.5% four years earlier.
The Social Democrats, who have served as coalition partners since 2013, initially rejected the chance to enter a new government with the CDU after their own disappointing election performance.
When Mrs Merkel failed to negotiate a coalition with two smaller parties the Social Democrats changed their position.
Mr Schulz told delegates before the vote: "Europe is waiting for a Germany that knows its responsibility for Europe and can act decisively."
Last September's vote was notable for the rise of the far-right Alternative for Germany party.