The shipment was revealed by investigative website Disclose, whose reporting on a similar shipment of French weapons earlier this month led to pressure that prompted Riyadh to renounce loading the weapons.

Disclose said the new shipment involved munitions for French Caesar cannons that would be loaded at the Mediterranean port of Fos-sur-Mer, near Marseille.

"I learned about the imminent arrival of the Bahri Tabuk cargo ship this morning," Pierre Dharreville, a communist MP for the Fos-sur-Mer region, told journalists, calling for a "moratorium" on arms deliveries to Saudi Arabia.

Rights groups accuse Riyadh of using the French weapons against civilians in Yemen, where around 10,000 people have died since it began its offensive in 2015 with its ally the United Arab Emirates.

French officials say the weapons have been used only for defensive purposes, rejecting claims that it is violating the Arms Trade Treaty that prohibits arms sales to countries if their use could lead to civilian casualties.

"Yes, it's a dirty war, yes it has to be stopped, Saudi Arabia and the Emirates must stop" the fighting, French Foreign Minister Jean-Yves Le Drian told France Inter radio on Tuesday.

"Yes, we must be extremely vigilant with arms sales to these two countries, which is what we are doing," he said.

But last month the Disclose website published findings from a classified French military note that said French weapons were being used in the Yemen war, contradicting the government's stance.

Three Disclose reporters were subsequently questioned by France's domestic intelligence agency, a move that drew protests from press freedom advocates.

France, the world's third-biggest arms exporter, counts Saudi Arabia and the United Arab Emirates as major clients and has resisted pressure to stop arms sales to the Gulf countries.

It is a marked contrast with Germany, which suspended its weapon sales to Saudi Arabia since last October.

The United Nations says the Yemeni conflict is the world's worst humanitarian crisis, with 3.3 million people displaced by the fighting and 24.1 million in need of aid.