Josh Frydenberg?s pick for ACCC chief represented bank in one of regulator?s biggest criminal cases

Josh Frydenberg's nomination for chair of the competition watchdog may have to recuse herself from any decisions relating to one of the regulator's biggest cases if she is approved for the job.

Gina Cass-Gottlieb, a partner at corporate law firm Gilbert & Tobin, has represented a key participant in a criminal case alleging cartel behaviour that the Australian Competition and Consumer Commission brought against ANZ, Deutsche Bank CitiGroup and banking executives over trading in ANZ shares.

If approved by the states and territories, she will replace Rod Sims, who has served as chair for more than a decade, and become the first woman in the ACCC's history to take the role.

The banking cartel case is one of the ACCC's most difficult, with a federal court judge last month describing the indictment brought by prosecutors as a "complete shemozzle" because charges had not been finalised more than three years after they were first laid.

Prosecutors also dropped the charges against ANZ and its senior executive, Rick Moscati, last month.

Cass-Gottlieb was closely involved in the case, acting on behalf of investment bank JP Morgan, which earned itself immunity from prosecution after agreeing to provide evidence against other alleged players.

She personally met with prosecutors in October and November last year to outline the evidence JP Morgan employees were willing to give in the case.