Speaking on Sunday, he said: "It is reprehensible that the man who wishes to be our Prime Minister honoured ruthless terrorists who committed an act described by the late King Hussein of Jordan as 'a savage crime against humanity'.
"This man is not fit to be a member of parliament, let alone a national leader. He has spent his entire political career cavorting with conspiracy theorists, terrorists and revolutionaries who seek to undo all the good for which our ancestors have given their lives.
"In so many ways, 'Enough is Enough'."
Mr Corbyn laid the wreath at a cemetary in Tunis in 2014.
Sources close to the leader said he was intending to pay tribute to 47 Palestinians killed in an Israeli airstrike in 1985.
But the Daily Mail reported that monument is 15 metres away from where Mr Corbyn was photographed laying a wreath, which was actually at the monument to members of Black September, who massacred 11 Israelis.
The latest revelation came after Board of Deputies president Marie van der Zyl urged Mr Corbyn to "come out of hiding" to deal with his party's antisemitism crisis.
She wrote: "He is clearly just hoping it will go away. I've got some bad news for him - unless he does what he needs to do, it won't."
