Leading German politicians and Israeli writers demanded yesterday that author Gunter Grass be sidelined as the Nobel laureate faced a growing backlash over his recent poem lambasting Israel.

Germany’s Social Democrats said Mr Grass was no longer welcome at their campaign rallies after last week’s publication of the hotly controversial work branding Israel as the Middle East’s biggest threat to peace.

The party’s chief whip, Christian Lange, told Die Welt newspaper that the notion of Grass, who had been appearing on the stump for the centre-left SPD since the 1960s, speaking on its behalf was now “out of the question”.

“I no longer want to see Grass in an SPD campaign,” another party official, Reinhold Robbe, told the daily ahead of two state elections in the next five weeks.

“Many Social Democrats would see campaign events with Grass as a provocation... His time is over,” he said, just as a group of Israeli authors demanded the Nobel prize committee denounce him – a move the Swedish Academy which chooses the literature winner said yesterday it would not do.

The deputy head of the SPD’s parliamentary group, Gernot Erler, told NDR public radio that 84-year-old Grass had “lost touch with reality”.

However, a former SPD parliamentary speaker, Wolfgang Thierse, told public broadcaster Deutschlandfunk that the party could criticise Grass’s views but “should not discredit him as a person”.