Iran has received "an oral invitation" to attend a planned Syria peace conference in Geneva next month, the official IRNA news agency quoted a deputy foreign minister as saying on Wednesday.

Hossein Amir Abdollahian said "an oral invitation" had been made "but we have not received a written one," according to the IRNA report.

He did not say who extended the invitation or when it had been sent out.

The United States and Russia are organising the conference in Geneva with the intention of bringing representatives of President Bashar al-Assad's regime and of rebel groups to discuss ways to end fighting that has claimed some 94,000 lives.

Abdollahian's remarks come as France has strongly opposed any participation by Iran, which has stood by its ally Assad, vowing to prevent his fall.

"Given that Iran does not want a political solution, bringing along that country... risks preventing a political solution rather than favouring one," French Foreign Minister Laurent Fabius said on Sunday.

Iran is accused by Western and Arab governments of supplying weapons and military advisers to its ally. Iran has repeatedly denied having any troops on the ground.

Russia has pushed hard for Iran to be invited to the Geneva conference, insisting it is "a very important outside player."

On Wednesday, Abdollahian told reporters: "Considering that the Geneva conference is focusing on a political solution, we will study any invitation in a positive light.

"Iran will not allow the fall of the Syrian regime," he said on the sideline of a forum Iran opened in Tehran on Wednesday to discuss its own proposals for ending the conflict in Syria.

Delegations from Russia, Nicaragua, Venezuela, Iraq and Algeria were among some reported 40 countries attending the Tehran meeting.

Earlier, Foreign Minister Ali Akbar Salehi had said, without elaborating, that Iran supports the "negotiations in Geneva."

Iran did not attend the previous Geneva meeting on the Syrian crisis in June 2012, which called for an immediate ceasefire. The United States and France had objected to its participation.