A Saudi cleric has appeared on television along with his wife, whose face was uncovered, in an open challenge to strict tradition of wearing niqab in the ultra-conservative kingdom.

Sheikh Ahmed al-Ghamedi, who has said covering the face is not a must for women under Islam, sat alongside his wife Jawaher bint Ali as she spoke to Dubai-based Saudi MBC television, in a programme broadcast at the weekend.

Saudi women rarely show their faces in public, but most Muslims worldwide see the practice of face-covering as part of tradition, not religion.

Sporting trendy sunglasses, light makeup and varnished nails, but also wearing the traditional black abaya cloak, Ghamedi's spouse spoke of the problems their children have at school because of their father's edicts, which are seen as liberal.

"Our children complain that some teachers tell them: why does your father say this and that?" she said of fatwas that have enraged ultra-conservatives in the desert kingdom.

Ghamedi, who once headed the religious police in the western city of Mecca, home to Islam's holiest shrine, has openly challenged the tradition of face veil on women.

He has also said that wearing makeup is permissible.

"The Prophet did not order women to cover their faces. Wearing make-up is allowed," he told Badria al-Bishr, female host of the television programme.

Saudi Arabia's top religious leader Sheikh Abdul Aziz al-Sheikh criticised Ghamedi on Saudi news website Sabq, urging him to repent and praying that "God will guide Ghamedi to the right path".

Saudi women cover themselves from head to toe when outside the home, and need permission from a male guardian to work and marry.

Saudi Arabia is also the world's only country which does not allow women to drive.