Victoria's Police Commissioner has moved to block the release of a report into police failures in the hours that led up to the Bourke Street massacre.

An elite police team refused multiple requests to intercept James Gargasoulas before he drove his car down Bourke Street on January 20, 2017, killing six people and injuring dozens of others.

A lawyer for the police told a coronial inquest on Tuesday that a report into police inaction and a statement from then assistant commissioner Doug Fryer were "sensitive" documents and police would fight to keep them secret.

Gargasoulas was jailed in February for at least 46 years for what the sentencing judge called one of Australia's "worst examples of mass murder".