Criminal solicitor Alex Lewenberg has been banned from practising law for 15 months after telling a Jewish sexual abuse victim not to help police prosecute Yeshivah College paedophile David Cyprys.

The lawyer, who has represented a string of notorious clients including Billy "The Texan" Longley and Boris "The Black Diamond" Beljajev, must also take an ethics course before being reinstated.

Alex Lewenberg, 74, can't practise law for 15 months and must take a legal ethics course after telling Jewish victim not to help police prosecute paedophile David Cyprys. Credit:Justin McManus

The 74-year-old was found guilty of professional misconduct by the Victorian Civil and Administrative Tribunal last month after the Legal Services Commissioner took action over two comments he admitted making in 2011.

On two occasions, once while in court for a bail hearing for Cyprys and later in a secretly recorded telephone conversation, Mr Lewenberg said that Jews shouldn't help prosecute fellow Jews.