Pope Francis reaffirmed his desire to visit Lebanon in a meeting on Thursday with prime minister-designate Saad Hariri, but the latter said it would only happen once a new government was formed.

During a private audience lasting around 30 minutes, the 84-year-old pontiff said he would like to visit Lebanon "as soon as the conditions are favourable", according to a Vatican statement.

He expressed his "closeness to the Lebanese people, who are experiencing a moment of great difficulty and uncertainty" and called upon "all political forces to urgently commit themselves to the benefit of the nation".

Hariri, a three-time premier selected in October to form a new government, told Lebanese media afterwards that the pope would visit "only after the formation of a government".

"That's a message for the Lebanese, that we must form a government, so that all the forces and all the people come together, so that we can take Lebanon forward with our friends," he said after the meeting, in comments broadcast on Lebanese television.

Pope Francis recently made a historic trip to Iraq, during which he repeated his desire to visit Lebanon.

The country was plunged into crisis following last year's devastating port blast in Beirut, which killed more than 200 people and forced the cabinet of outgoing premier Hassan Diab to resign.

It compounded Lebanon's worst economic crisis since the 1975-1990 civil war, but political leaders have yet to agree on a new government.