The brother of an Australian terrorist suspect detained in Lebanon has been arrested in Iraq by a Kurdish political organisation.

Ahmad Jamal, 22, from Sydney, has been detained by the Patriotic Union of Kurdistan (PUK) in northern Iraq, the Department of Foreign Affairs and Trade (DFAT) said today.

The department was notified of his detention by the International Committee of the Red Cross.

"Consular officials in Baghdad have spoken to PUK officials and continue to press for confirmation of his detention and its legal basis," a DFAT spokesman said.

"Our efforts to date have been unsuccessful and we're following up with (Red Cross) officials to obtain further information. We're doing that through our consular official Amman in Jordan."

It was not known when the man was detained, the spokesman said.

Sydney's Daily Telegraph newspaper reports his father has said Ahmad was arrested over confusion with his identification.

Ahmad Jamal is the brother of Saleh Jamal who was arrested six months ago in Lebanon after skipping bail in Sydney on charges of shooting up the Lakemba police station in 1998.

Lebanese officials claim Saleh Jamal has links to the most wanted terrorist in Iraq, Jordanian Abu Musab al-Zarqawi.