A traffic light in Munich | Joerg Koch/Getty Images Germany’s SPD calls for gay marriage vote after Merkel softens stance SPD made legalization of gay marriage a condition to join a coalition government.

A day after Angela Merkel said same-sex marriage should be a "decision of conscience," the Social Democrats (SPD) called for a vote on the issue in the Bundestag this week.

In an interview with women's magazine Brigitte on Monday, Merkel said she did not believe gay marriage should be a party-political issue. Merkel's Christian Democratic Union has been traditionally opposed to same-sex marriage but all of its potential coalition partners support legalization, including the SPD.

In response to her remarks, Merkel's rival for the German chancellorship, Martin Schulz, called for a vote on legalizing gay marriage to be held this week, the Associated Press reported.

"Angela Merkel made ... a move yesterday and we are taking her at her word," Schulz said at a press conference in Berlin. He added that her "change of heart ... should be concluded this week."

Schulz doubled down on his stance in a tweet Tuesday afternoon.

We will push through marriage equality in Germany. This week. — Martin Schulz (@MartinSchulz) June 27, 2017

While Schulz and the SPD saw a boost in popularity when he announced his candidacy in January, he currently trails Merkel by a wide margin in the race for the German chancellorship. The SPD have made the legalization of gay marriage a condition for them joining a coalition government after the September 24 election.

Earlier Tuesday, CDU chief whip Michael Grosse-Broemer said there was “no need for a rushed decision.”

Germany has allowed same-sex couples to enter into civil partnerships since 2001.