Gilad Shalit’s father has said his son’s captivity is the obstacle preventing Gaza from overcoming “economic chokehold”.
Noam Shalit said that if Hamas were to agree a deal to release the soldier, kidnapped nearly four years ago, it would encourage Israel to lift the blockade of Gaza.
He told a Jerusalem conference that the continued imprisonment of the soldier for the purpose of bargaining and political blackmail “is a grave war crime”.
Calling on Hamas to release him, Mr Shalit said: "This will allow for rebuilding the ruins in Gaza in wake of Operation Cast Lead.”
His comments follow the decision by Israel to ease the blockade of Gaza and allow good including Coca Cola into the area.
Gilad Shalit was captured in June 2006 at the age of 19. Hamas has consistently refused to give out information about his welfare and has rejected a deal for a prisoner exchange.
Mr Shalit also told the conference that appeals for help from the pro-Palestinian activists on board the Gaza-bound flotilla had been unsuccessful.
He said: "We asked whether it would be possible to transfer something humanitarian to Gilad; a letter from his father, from his mother, or from his sister.
“Regrettably, the sail organisers refused."
The Gilad Shalit campaign has recently received support from a high profile source. California governor Arnold Schwarzenegger told a Los Angeles rally that the missing soldier was in his prayers.