Lebanon's caretaker prime minister has pleaded in Paris for support for his nation's army which would help secure any ceasefire, but a low-level US presence at the conference in France and a looming US election dimmed prospects for a swift halt to fighting.

Some 70 government delegations and 15 international organisations met in Paris on Thursday, aiming to raise at least 500 million euros ($540 million) in humanitarian aid and push for a ceasefire, but with the US focused on its own efforts, diplomats said they expect little concrete progress.

"The storm we are currently witnessing is unlike any other, because it carries the seeds of total destruction, not only for our country, but for all human values as well," Lebanon's Najib Mikati told delegates.

Mikati said international support would be needed to shore up the army, including new recruits, and to rebuild the country's destroyed infrastructure.

France has historical ties with Lebanon and has been working with Washington in trying to secure a ceasefire.

But after Israel rebuffed a 21-day ceasefire plan in September, Paris' influence has been limited since Israel launched its large-scale onslaught on southern Lebanon that has killed more than 2,000 people and displaced at least 1.2 million.

Ceasefire calls

Opening the conference, France's President Emmanuel Macron said there would not be a return to the past in Lebanon and that a UN Security Council resolution that had failed to keep the peace would need to be fully implemented.

"There needs to be a ceasefire in Lebanon. More damage, more victims, more strikes will not enable the end of terrorism or ensure security for everyone," he said.

Despite the repeated calls for a ceasefire, there appeared no sign on Thursday of the conflict abating.

US Secretary of State Antony Blinken, who skipped the Paris conference, continued a tour of the Middle East on a final push for peace before next month's US election, while regional power Saudi Arabia, which has been reluctant to engage in Lebanon, sent a junior minister.

Neither Israel, whose prime minister, Benjamin Netanyahu, criticised the initiative, nor Iran were invited.

Macron said France would provide 100 million euros ($108 million) in aid, while Germany said it would give 96 million euros ($103 million). France's foreign ministry said the conference aimed to raise at least 500 million euros ($540 million) to primarily help up to one million displaced with food, healthcare and education.

Lebanon says it n eeds $250 million a month to deal with the crisis.