The former head of the CFMEU, John Maitland, has been found guilty of misleading New South Wales' corruption commission.

Maitland was interviewed by the Independent Commission Against Corruption (ICAC) in 2012 over a licence granted to Doyles Creek Mining, a company he once chaired.

He later told the commission under oath that he had not discussed his evidence with anyone, despite being caught on tape discussing it with a friend.

Maitland told the court he had simply forgotten about the conversation, but the magistrate did not accept his explanation.

Maitland could face a prison term for misleading ICAC.

When the ABC asked Maitland if he was concerned about a potential jail term, he replied "Merry Christmas".

He will be sentenced next year.