Lobbying of federal ministers must be the next anti-corruption focus, a retired Victorian Supreme Court judge has asserted in an annual speech in honour of one of the country's most well-known corruption fighters.

Justice Stephen Charles gave the Tony Fitzgerald Lecture at Griffith University on Thursday night amid continuing debate about the shape of the Commonwealth Integrity Commission, announced by the Morrison government in December 2018.

Justice Stephen Charles.

Justice Charles is a scathing critic of the Commonwealth Integrity Commission model being proposed, describing it as “too weak and too narrow" and only likely to investigate blatant “brown-paper-bag bribery”.

“The Commonwealth Integrity Commission model will not permit any investigation of electoral donations or their consequences, nor of the revolving door movement of ministers and public servants into private industry,” he said.