The Supreme Court of Victoria has ruled The Age newspaper will not have to reveal its sources over a series of articles written about a businessman it said had links to the mafia.

Grocer Antonio Madafferi claimed he had been defamed in 12 articles about allegations of criminal misconduct involving the Calabrian community in Australia.

Mr Madafferi has never been charged with any offence and has denied he is involved with organised crime.

He had applied for the investigative journalists to reveal the identity of their sources so their credibility could be examined.

Justice John Dixon today dismissed Mr Madafferi's application.

He said the public interest was not strong enough for the sources to be revealed.

A defamation trial against The Age begins in August.