AMSTERDAM (Reuters) - A Lebanese journalist was fined on Monday for disclosing the names of protected witnesses at the international tribunal investigating the murder of Lebanese Prime Minister Rafik al-Hariri in 2005.

Ibrahim Al Amin and the publisher of the Akhbar Beirut newspaper, Akhbar Beirut S.A.L, were fined 20,000 and 6,000 euros respectively. The court ordered that the fine be paid by Sept. 30.

It was the latest in a series of contempt hearings at the Special Tribunal for Lebanon, set up in 2009 to investigate the murder of Hariri and 22 others on Feb. 14, 2005.

Al Amin and his publisher were convicted in July of "knowingly and wilfully interfering with the administration of justice by publishing information on purported confidential witnesses," the court said.

The tribunal's maximum penalty for contempt is imprisonment of up to seven years in prison and a fine of up to 100,000 euros.

(Reporting By Anthony Deutsch; Editing by Richard Balmforth)