Mr Deane gave several reasons why Mr Geldof should "not choose the side of the oppressor" by visiting Israel, citing recent boycotts by Elvis Costello and Pink Floyd's Roger Waters and the decision of the University of Johannesburg to sever its longstanding links with BGU.
He also said Mr Geldof should consider whether it was "appropriate" to attend the IsraAid conference because "the criminal actions of the Israeli state have resulted in the Palestinians being more dependent on humanitarian aid than any people on earth".
Mr Deane went on to add that if his appeal was ignored, the singer "may well stand accused of placing the oppressor's flattery above the victim's plea for solidarity."
He wrote: "You will have lent yourself heedlessly to exploitation by a rogue state that has mastered the art of propaganda and whitewash".
Mr Geldof has yet to respond.