Jeremy Corbyn has pledged to visit Israel again despite saying he is unable to take up an invitation from Isaac Herzog to go to the country and visit Yad Vashem “in the immediate future”.

The Labour leader said diary commitments prevented him from visiting now and he’d instead asked deputy Tom Watson or Labour general secretary Ian McNicol to look at the possibility of going “on my behalf”.

“I look forward to the chance to meet and exchange views as soon as possible,” he added in a letter to the leader of the sister party in Israel more than a month after the invite.

He also insisted “every” allegation of anti-Semitism in the party had led to “immediate action” and said the party under his leadership would build on Labour’s proud anti-racist record. Herzog had written in disgust in May following the suspension of Naz Shah for endorsing a social media post urging the transportation of Israel to America and subsequent action against Ken Livingstone, who attempted to defend her by saying that Hitler’s policy in 1932 was that “Jews should be moved to Israel”.

He invited Corbyn to visit Yad Vashem to see that the last time Jews “were forcibly transported it was not to Israel but to their deaths”. Expressing disappointment at the response, Labour Friends of Israel’s Joan Ryan said such a visit should have been a priority in light of Corbyn’s record on the Middle East.

A spokesman for Corbyn said: “He has visited Israel on more than a dozen occasions and will do so again. He just told Isaac Herzog he is unable to in the immediate future.”