A former judge now representing Tony Mokbel pro bono has accused Victoria Police of criminal behaviour and says the drug lord has grounds to be freed from prison.

A cavalcade of defence lawyers representing the who's who of Melbourne’s underworld appeared before the Lawyer X royal commission on Wednesday.

The commission is investigating the conduct of the force and its prized informer, former gangland barrister turned supergrass Nicola Gobbo.

Nicola Gobbo leaves court with drug boss Tony Mokbel. Credit:ninevms

Lawyers for Mokbel, drug traffickers Francesco Madafferi, Pat Barbaro, Rob Karam and Pasquale Sergi, as well as gangland getaway driver Faruk Orman, slammed Victoria Police over its lack of disclosure of documents that could free their clients.