The ABC has been cleared of systemic "anti-business" bias in a major review of its coverage, with former ANZ boss Mike Smith confessing he has rethought his negative perceptions of the broadcaster.

The independent editorial review, for which Mr Smith was a key adviser, has been one of the broadcaster's most comprehensive yet. As well as analysing a week's worth of ABC programming, the review included interviews with ABC business staff and submissions from business groups, think-tanks and unions.

Former ANZ bank boss Mike Smith says he has rethought his negative perceptions of the ABC. Credit:Pat Scala

Fairfax Media understands the review, which has not been released publicly, is overwhelmingly positive about the ABC's coverage overall while making some criticisms.

Sources familiar with the review, led by longtime BBC adviser Kerry Blackburn, said they were relieved and surprised by its positive tone.