David Ward is facing disciplinary action after accusing “the Jews” of inflicting “atrocities on the Palestinians” within “a few years of liberation from the death camps”.
The MP for Bradford East later took down the comments from his website, amid criticism from his own party.
The row comes as victims of Nazi persecution prepare to mark Holocaust Memorial Day on Sunday.
On the page, Mr Ward said he had “signed a Book of Commitment in the House of Commons, in doing so pledging his commitment to Holocaust Memorial Day” and describes Auschwitz as “the Nazi concentration and extermination camp which is the site of the largest mass murder in history”.
But he added: “Having visited Auschwitz twice – once with my family and once with local schools – I am saddened that the Jews, who suffered unbelievable levels of persecution during the Holocaust, could within a few years of liberation from the death camps be inflicting atrocities on Palestinians in the new State of Israel and continue to do so on a daily basis in the West Bank and Gaza.”
A Liberal Democrat spokesman said disciplinary action against Mr Ward is an internal party matter.
He added: “This is a matter we take extremely seriously. The Liberal Democrats deeply regret and condemn the statement issued by David Ward and his use of language which is unacceptable.”
Baroness Tonge quit as a Liberal peer in the House of Lords in 2010 after refusing to apologise for claiming that Israel would not “last forever”