French president Emmanuel Macron will return to Lebanon in December for his third visit to the crisis-hit country since a devastating August explosion in Beirut, the French presidency told AFP on Tuesday.

Macron, who landed in the Lebanese capital on Monday for a two-day trip, has taken centre stage in an international push for long-overdue reforms. 

This was his second visit since the August 4 explosion at Beirut's port killed more than 180 people, wounded at least 6,500 and laid to waste swathes of the capital. 

On Tuesday, Macron said he was ready to organise an international aid conference for Lebanon in October which, if it happens, would be the second such effort to be led by Paris since the August 4 blast. 

Speaking to French news outlet Brut, Macron said he would "follow up" on progress made by Lebanese leaders towards enacting reform "in October and then in December."

"I will personally commit myself to it," he added, vowing to block aid money donors have pledged to Lebanon if changes are not made. 

Beyond a planned aid conference in October, "I will also come back in December," he said, which his office later confirmed to AFP. 

The Beirut explosion compounded Lebanon's worst economic crisis since the 1975-1990 civil war, with a UN agency warning on Sunday that more than half of the population risks a food crisis by the end of the year.

The blast caused up to $4.6 billion worth of damage and a blow to economic activity of up to $3.5 billion, according to a World Bank assessment. 

On August 9, international donors pledged 252.7 million euros (around $300 million) in emergency aid during a video conference jointly organised by France and the United Nations.

But donors vowed that aid would bypass political leaders, whose corruption and ineptitude is widely blamed for Lebanon's economic crisis as well as the port blast.

Macron has said it was not his place to "approve" Monday's designation of Mustapha Adib as prime minister.

But the little-known 48-year-old diplomat "has to be given all the tools to succeed... so he can implement reforms" long demanded by the international community, Macron said on Tuesday.