German author who sparked recent controversy with poem criticising Israel is expected to remain in hospital for a few days

The German author Günter Grass is expected to stay in hospital for several days after being admitted for "a scheduled investigation", according to a spokeswoman.

Grass, 84, who this month sparked international controversy with a prose poem in which he criticised Israel´s stance towards Iran, was taken to the Asklepios Clinic in Hamburg by his wife on Monday.

A hospital spokesman confirmed that the writer had been admitted to the clinic but refused to give further details, fuelling speculation that the debate has taken its toll on his health.

The news agency DPA quoted Grass´s doctor, Karl-Heinz Kuck, confirming newspaper reports that the writer had heart problems and was under observation at the clinic, but refused to go into detail. He said: "He is not having to lie in bed, he´s working and enjoying the view from his room."

His spokeswoman, Hilke Ohsoling, said that Grass´s health problems had not been triggered by the debacle over his poem. "He is 84 years old and who doesn´t have any health problems at that age?"

Grass´s office said the admission had been planned for some time. "Mrs Grass took her husband to a Hamburg hospital to undergo a scheduled investigation," his spokeswoman said. "We are expecting that he will be home again within the next few days." She refused to give any more details about his condition.

The Nobel laureate caused outrage at home and abroad with the newspaper publication two weeks ago of his poem, What Must Be Said, in which he said he feared Israel was capable of "wiping out the Iranian people" with a single nuclear strike.

It led to criticism that Grass had adopted antisemitic cliches and was downplaying the threat Tehran posed. Israel has since banned Grass from entering the country.

Grass appeared shocked by the reaction his poem triggered. In an interview with the Süddeutsche Zeitung, he said he had expected fierce reactions but not "that the offensive and blanket reproach of antisemitism would be levied against me … I had hoped for a clearer debate".

He added that in hindsight he would have changed his poem slightly, "avoiding the blanket term Israel, and making it clearer that I was primarily referring to the current government of Netanyahu". (guardian.co.uk © Guardian News and Media Limited 2012 04/18/12)