The Australian confirms John Howard tried and succeeded in crushing dissent at the ABC :

When the Australian Broadcasting Corporation launched its political analysis program Insiders in 2001 the public broadcaster's own staff were forbidden from being panelists.

John Howard's coalition government was closely monitoring the ABC, which it viewed as enemy territory, and network programmers mindful of not agitating outspoken communications minister Richard Alston approved the show on condition only external commentators representing a spectrum of different views were used.

And yet, despite very strong opinions and criticisms from ABC journalists and commentators against prime minister Kevin Rudd all over ABC radio, TV and online, not one journalist has so far revealed any pressure coming from the PM's office to tone it down or shut up.