Junior partner to Merkel's conservative Christian Democrats, the Social Democrats (SPD) have been irked by her support for fellow conservative Barroso, as he plumps for a second term at the head of the European Union's executive arm.
“The chancellor shouldn't raise her hand for Barroso,” Angelica Schwall-Düren, deputy head of the SPD's parliamentary group, told the Berliner Zeitung on Thursday.
She also said Barroso had yet to present a promising strategy for tackling the EU's problems over the next five years.
“That's why the SPD is against Barroso remaining president of the Commission,” she said.
EU issues are frequently becoming more contentious between Merkel's conservatives and the SPD in the run-up to German general election in September.
After winning the June 7 European Parliament poll, the Christian Democrats said they had a right to nominate Germany's next EU commissioner, but the SPD wants to keep one of their own in the post.