Germany's Social Democratic Party (SPD) leader Martin Schulz would not be the right replacement for Chancellor Angela Merkel because of his choice to prioritize the needs of Greek communists over German taxpayers, Germany's deputy finance minister Jens Spahn told CNBC on Wednesday.
"(Schulz) is part of the political elite in Brussels and Berlin but he tries to shape himself as someone from outside and so far it seems to work but of course we have to tackle him on this and to ask him about his positions in the past," Spahn told CNBC on Wednesday.
"He was always a better friend to the communists in Athens than to the German taxpayers and that for example is an issue we will bring up," he added.
SPD party delegates officially backed Schulz with 100 percent of the vote on Sunday as they nominated the former European Parliament president as their new leader.
Schulz's approval ratings have rocketed skywards in recent months and the center-left candidate now finds himself as the political frontrunner to become Germany's new premier, according to the latest opinion polls.
Merkel and Spahn's Chrisitan Democratic Union (CDU) were accused of showing signs of nervousness in response to the deputy finance minister's remarks on Wednesday, an SPD spokesperson told CNBC via email.
"It's obvious that the CDU is quite nervous about the outstanding performance of Martin Schulz. Spahn's comments are hilarious at best. Our campaign will be about policy and not about personal attacks," Niels Annen, SPD foreign affairs spokesperson, told CNBC via email.