RNZ and its corporate culture has been heavily criticised for resisting change by former journalists such as Sean Plunket, who left National Radio for commercial radio.
Supporters of Cavanagh - an Australian who came to RNZ from the SBS public broadcasting system - say he provided stability after a period of upheavals and maintained its integrity.
Critics say that has been at the expense of innovation and by resisting Government calls for new funding sources.
Government calls for change were rejected following a successful Save Radio New Zealand Facebook campaign in February 2010.
This week RNZ claimed healthy ratings results from survey company Nielsen, which suggested National Radio is the most listened-to talk radio station in New Zealand - for the second survey in a row.
However, commercial radio industry body the Radio Broadcasters Association said the RNZ survey was not comparable with its biannual surveys conducted by Research International.
That survey's result from August suggested Newstalk ZB was the most-listened-to talk radio station.