French President Emmanuel Macron will be in Beirut in December for the third time in four months.
Mr Macron made the announcement in his opening speech for the second humanitarian conference for Lebanon after a deadly explosion tore through the capital in August, killing more than 190 people.
"This second conference will allow us to complete the emergency response and early recovery," Mr Macron said.
"But it cannot substitute the need for Lebanese political leaders and institutions to form a new government quickly and enact a roadmap for reform that is necessary to access international economic relief."
He said a fund managed by the World Bank, the EU and the UN will be set up to handle humanitarian aid for Lebanon.
Mr Macron is personally involved in helping Lebanon to escape economic crisis and recover from the blast.
But political leaders have so far failed to form a new government and implement reforms to fight corruption, which are required to unlock billions in international funds from donor countries and the International Monetary Fund.
Mr Macron criticised politicians, saying they were not keeping their promises to enact reforms.
"To this day, it appears these were merely words," he said.
Lebanese Prime Minister Hassan Diab stepped down after the explosion on August 11. His caretaker Cabinet has not been replaced.
Mr Macron's visit will be his third to Beirut since the explosion and will try to pressure leaders into action after a four-month deadlock in forming a new government.
Also speaking at the conference, Lebanese President Michel Aoun said he wanted to fight corruption by conducting a forensic audit of the Lebanese Central Bank, "no matter what it will cost me".
Mr Aoun said the results of the audit would "free the Lebanese state from a system of economic, political and administrative corruption".
The Lebanese government signed a contract with financial consultancy Alvarez and Marsal in August to conduct the audit.
But the company resigned after the Banque du Liban refused to hand over all the required information, citing banking secrecy laws.
In the past week, the Lebanese Parliament voted on a non-binding decision that public entities could be audited without being hindered by factors such as banking secrecy laws.
Lebanon is also in talks with the World Bank for a $246 million loan to be used as a social safety net and for fighting Covid-19, Mr Aoun said.
