Berlin: Germany's main opposition party piled pressure on Chancellor Angela Merkel on Sunday over a scandal dogging her handpicked candidate for president, calling for new elections if he were to step down.

As new revelations emerge almost daily about Christian Wulff, 52, and a home loan affair that has dominated the country's media for weeks, a senior member of the opposition Social Democrats (SPD) sought to shift the heat onto Merkel.

The party's secretary general, Andrea Nahles, told the Bild am Sonntag weekly: "If Wulff resigns, then there should be new elections ... the Wulff affair is also a Merkel affair."

"Christian Wulff is not up to the office of federal president. Staying in office, no matter what happens? That behaviour is not acceptable ... I have serious doubts that he will survive this affair," added Nahles.

The office of president is largely ceremonial. Wulff started his five-year term in 2010.

The scandal broke in December when mass circulation Bild reported that Wulff failed to declare a loan he had obtained from the wife of a wealthy tycoon when he was the leader of the state of Lower Saxony.

On learning the story was about to break, Wulff left furious voicemail messages with the Bild's chief editor and reportedly also the chief executive of the paper's publisher.

According to Spiegel newsweekly, Wulff asked to discuss the story on his return from an official trip "and then we can decide how we see things and then we can decide how we should wage war."

As recently as Friday, Merkel's spokesman said she had "great esteem" for Wulff both as a person and as a president, but the scandal is an increasingly unwelcome distraction as she seeks to focus on the eurozone debt crisis.

However, as hundreds protested outside Wulff's official residence in Berlin over the weekend and polls on Sunday showing Germans believed he had lost credibility, Wulff himself reportedly sought to shrug off the scandal.

"In a year, this will all be forgotten," he told staff members, according to the Bild am Sonntag.

Tags: Angela Merkel, Angela Merkel scandal, Germany