The case was lodged by a Dutch-Palestinian man, Ismail Ziada, six of whose relatives were killed in Operation Protective Edge, a major Israeli military operation targeting Gaza.

But the court said that under international law it could not hear the case, which named Gantz -- the main political rival of Prime Minister Benjamin Netanyahu -- and former Israeli air force chief Amir Eshel.

"The district court has ruled that the Dutch court is not competent to hear the case, because the former Israeli officials have functional immunity from jurisdiction," Judge Larisa Alwin said at The Hague district court.

"This form of immunity, a legal concept in customary international law derived from state immunity, applies to acts carried out in the performance of a public duty," she said.

"The air strike in the Gaza Strip, in which six of the claimant's relatives were killed, is an example of an act carried out in the performance of a public duty."

Gantz was the chief of general staff of the Israeli defence force at the time of the Gaza bombing as part of Operation Protective Edge.

Ziada's mother, three brothers, a sister-in-law, a young nephew and a friend were killed in the strike on Bureij refugee camp in Gaza on July 20, 2014.

Israel said it launched Protective Edge at the time to stop rocket fire against its citizens and destroy tunnels used for smuggling weapons and militants.

At a hearing in September Ziada told judges he was "seeking justice" and would not get a fair hearing before an Israeli court.

"The claimant believes that he cannot file his claim anywhere else and that the case has sufficient ties with the Netherlands, because he holds Dutch nationality and lives in the Netherlands," the court said.

In total, Operation Protective Edge left 2,251 dead on the Palestinian side, most of them civilians, and 74 on the Israeli side, most of them soldiers.