A parishioner who launched a Facebook tirade against the archbishop of his church has been ordered to pay $150,000 in damages after the religious leader sued him for defamation in the NSW Supreme Court.

Mar Meelis Zaia, the Archbishop of the Assyrian Church of the East in Australia, took legal action against former parishioner Sargon Eshow after Mr Eshow waged what Justice Lucy McCallum described as a "campaign of criticism" against him online.

Mar Meelis Zaia, Archbishop of the Assyrian Church of the East in Australia, pictured in 2014 with then premier Barry O'Farrell. Credit:Wesley Lonergan

Mr Eshow was suspended from the church for two years from April 2015 after he published two posts on his Facebook page in Arabic criticising the appointment of two priests.

He was told to stop posting "defaming information on Facebook" and was warned that any future "misbehaviour" or "disturbance" would not be tolerated. He published a series of posts later that year.