A Saudi man suspected of links to al Qaeda has been arrested in one of Saudi Arabia's major oil centres, a government spokesman said on Wednesday.

Ahmad al-Hadhli was arrested on Friday in the Red Sea port city of Yanbu, Mansour al-Turki, the Interior Ministry spokesman for security affairs, said.

Hadhli, 36, was on a wanted list of 85 people issued by the Saudi authorities last year.

A security source said Hadhli had been monitoring oil and industrial facilities at Yanbu, site of a large oil refinery, an oil terminal and petrochemical plants.

Turki declined to comment, saying Hadhli was still being questioned.

Turki declined to comment on reports that Saudi Arabia was holding Abdullah Saleh al-Eidan, an alleged al Qaeda field commander caught in January with documents and the contact details of some 300 people in Oman.

Reuters