The advice by Supreme Court Advocate-General Paul Vlas comes after an appeals court in February ordered the Dutch state to "put an end to further export of F-35 parts to Israel".

The appeals court said at the time there was a "clear risk" the planes would be involved in breaking international humanitarian law.

State lawyers appealed against the verdict before the Supreme Court, which was now due to hand down a final ruling.

"The Hague Appeals Court ruling that the Dutch State must put an end to the export of F-35 parts to Israel can remain in place," Vlas advised the Supreme Court's judges.

Vlas' assessment was "based on various international regulations to which the Netherlands is a party, (and) the export of military goods must be prohibited if there is such a clear risk" of breaking them, the Hague-based Supreme Court said in a statement.

A group of human rights organisations initially brought the case, arguing that the parts contributed to violations of law by Israel in its war on Gaza.

The 13-month Israeli war on Gaza, deemed genocidal by the International Court of Justice, has so far claimed the lives of at least 44,363 people and injured more than 105,070 others in the strip, according to Gaza's health ministry.

In December, the District Court in The Hague had said that supplying the parts was primarily a political decision that judges should not interfere with.

But that ruling was then overturned by an appeals court in February.

The Dutch Supreme Court has several advocate-generals, who serve as independent jurors with "broad professional experience" and advise the court's judges before a final verdict.

Although the Supreme Court is not obliged to follow this advice, it was often seriously considered and could serve as a bellwether to the final decision.

"The Supreme Court will issue a ruling as soon as possible," the court said.

*This story was edited by Ahram Online.