The head of Germany's most prominent circus has criticised Social Democratic candidate Peer Steinbrueck for comparing the clown profession to former Italian prime minister Silvio Berlusconi.

Italy-German relations were strained after Steinbrueck said he was "horrified that two clowns won the election", referring to centre-right leader Berlusconi and comic-turned-politician Beppe Grillo.

He called Berlusconi "clearly a clown with a testosterone boost".

But the comparison has angered Bernhard Paul, director of Circus Roncalli. "[A circus clown] is no fool who can be placed on the same level as Berlusconi", he said, according to German news agency DPA.

"Being a clown is an honorable, very difficult, sensitive and artistic occupation," he said. "How can you compare that with bunga-bunga?"

Steinbrueck remarks led to the cancellation of a dinner with Italy's President Giorgio Napolitano, who was on official visit to Germany.

The German candidate's spokesman said Napolitano cancelled "because of Steinbrueck's remarks on Tuesday" and added that the SPD politician "understood Napolitano's domestic political reasons for cancelling".

Volker Wissing, senior parliamentarian with Germany's Free Democrats, Merkel's junior coalition partners, said the Social Democrat candidate was "mutating into a German Berlusconi".

Social Democrats were not impressed by Steinbrueck remarks either.

"We can't take the election result in Italy lightly or interpret it as a slip-up," said Peter Friedrich of the SPD, the minister for European affairs in the state government of Baden-Württemberg.

This week's Economist front page features identikit images of Grillo and Berlusconi with the headline, Italy's election: Send in the clowns.

Circus Clowns: Please Don't Compare us to Silvio Berlusconi
Circus clown: A more honorable profession than politics?