French President Francois Hollande voiced support on Sunday for a transitional Syrian opposition government and called Iran's nuclear ambitions a "threat" to the region and the world.

"France is very keen on the formation by the opposition of a transitional government that would give it full legitimacy and ensure democratic transition in Syria," he told reporters after meeting Saudi King Abdullah.

It is "absolutely necessary for the opposition to restructure," he said, as the Syrian National Council began meetings aimed at broadening its membership which has been criticised by the US.

Details have emerged of plans to reshape the SNC into a representative government-in-exile, after US Secretary of State Hillary Clinton charged that the opposition bloc, in its current structure, was not representative.

Asked about military aid to the Syrian rebels, Hollande said that only if "a temporary government is formed... we could only then ensure where the arms that could one day be provided go."

Syria has been rocked by a deadly war that a rights group says has left more than 36,000 people dead since the uprising against President Bashar al-Assad's rule erupted in March 2011.

Paris and Riyadh have "very similar views" on the nearly 20-month conflict, French sources had said.

On Iran's controversial nuclear programme which he discussed with the Saudi monarch, Hollande stressed that Tehran's will to "access nuclear weapons" is seen as "a threat to the entire region and for the world."

Paris and Riyadh "agree" on toughening sanctions against Iran to "prevent it from moving forward" with its nuclear programme, he said. But both countries stressed negotiations with Iran as a way to resolve the matter.

Iran denies Israeli and Western suspicions that its nuclear programme is a cover for efforts to build an atomic bomb, but has been hit by several rounds of UN and Western sanctions.

Hollande's stop in Jeddah came after a brief visit to Beirut during which he pledged to protect Lebanon against threats of destabilisation caused by the conflict in neighbouring Syria.

In Jeddah, he spoke of a "common position" between France and the kingdom over Lebanon: "We once again warn all those who would destabilise this country which needs to regain its unity through dialogue."

Both leaders also discussed the Middle East peace process, according to spokesman Romain Nadal.

Hollande earlier told reporters that "this visit to Saudi Arabia is primarily political."

"France plays an active role in the Middle East. We are the most active country on issues concerning Syria, Lebanon, and the peace process" between Israel and the Palestinians, he said.

He later added that his stopover aims at "establishing a personal relationship" with the monarch, whose country "is France's first trade partner."

"I welcome Saudi Arabia's attitude in increasing its (OPEC) production quotas, allowing (oil) prices to remain under control," he said, adding that the kingdom will contribute "to the recovery of" the world economy.

A French minister who requested anonymity said Hollande's visit was aimed at improving relations with the kingdom which chilled under France's former head of state, Nicolas Sarkozy.

"Things weren't working well. They weren't so good and now we are trying to have something else," he said.

During his brief visit, Hollande also met three civil society representatives with whom he discussed reform in the absolute monarchy as well the rights of women in the only country where they are banned from driving, a French diplomatic source said.

"Since 2005 (when King Abdullah came to power), steps have been completed and hopes are for more to be done on human rights and the situation of women" in the ultra-conservative kingdom, Hollande told reporters.

His trips to Lebanon and Saudi Arabia came as he headed for an Asia-Europe (ASEM) summit in Laos on Monday against the backdrop of the eurozone economic crisis and lower growth forecast in Asia.

The two-day summit gathers all 27 EU member states and 21 from Asia, including China and India, growth engines which have both come under pressure as the eurozone debt crisis has undercut demand for their exports.