French far-right presidential hopeful Marine Le Pen walked out of a planned meeting with Lebanon's Grand Mufti when she was asked to wear a Muslim headscarf.

Le Pen, who is leader of the populist Front National party, had been scheduled to meet Mufti Deryan on Tuesday morning as part of her three-day visit to Lebanon.

"You can pass on my respects to the Grand Mufti, but I will not cover myself up," Le Pen told reporters.

The press office for the Mufti told Reuters that Le Pen had been informed of the necessity of wearing a headscarf ahead of the meeting.

Le Pen is visiting Lebanon to meet key officials as part of her bid to boost her presidential credentials.

Le Pen is currently leading polls ahead of the first round of the French presidential election on April 23. Polls also show her trailing in the second round run-off in May, though she has in recent weeks halved the lead of her main rival, independent Emmanuel Macron.

She has campaigned on an anti-Islam, anti-EU platform, and is believed to have gained support from increasing concern about France's security situation following a series of Islamist terror attacks.