The Labor frontbencher Brendan O’Connor has accused the Abbott government of organising “an assault on the ABC” in a quest to silence independent media voices.

Tony Abbott and his communications minister, Malcolm Turnbull, have told the national broadcaster it made an error of judgment by agreeing to partner with Guardian Australia to reveal Australia’s past attempts to spy on the Indonesian president. The story led to a serious rift in Australia’s relationship with Indonesia.

O’Connor described the ABC as an important institution that needed to maintain sufficient funding “so we can have an independent voice in the media”. In a speech to parliament he condemned Turnbull for conveying his concerns directly to the ABC managing director Mark Scott and attacked Liberal senator Cory Bernardi for seeking to slash the publicly funded broadcaster’s budget.

O’Connor accused the government of working in concert with News Corp commentators to bully the ABC. Those commentators were “jumping on the bandwagon, with, I would suggest, a conflict of interest, working as they do for other media outlets”.

“Janet Albrechtsen called for the sacking of Mark Scott, and the journalist Greg Sheridan called the ABC an ideological institution. This is an assault on the ABC that looks very much organised, organised by those members of the government that want to see the end of an independent voice in this country, a statutory body that has served listeners and viewers well over many, many years,” O’Connor said.

“They want to cow the ABC into reporting in a way favourable to the government. I understand that, because some of the reporting of some private organisations may favour the government, which is entirely up to those organisations, the government may not understand what an independent voice is. They so often see media outlets defend or rationalise, or give the view of a government such favour, that they cannot hear an independent voice when they are listening to one. But the fact is this: in a civil democracy it is vital that there is public money put aside to ensure that vested interests alone do not prevail in this space.”

Coalition parliamentarians, including Bernardi, used a joint party meeting last week to criticise the ABC. The meeting heard claims the ABC was in breach of its charter and cannibalising the local media landscape, had too many TV channels and was a taxpayer-funded behemoth. Turnbull rejected some of the criticism but referred to “last-century work practices” at the broadcaster, in a signal of possible reform plans.

Scott last week defended the ABC’s decision to publish with Guardian Australia material revealing that Australian intelligence had targeted the mobile phones of the Indonesian president, his wife and his inner circle. The story was based on a top-secret document dated November 2009 leaked by the former US intelligence contractor Edward Snowden.

Scott said it would be wrong for an independent broadcaster to walk away from a story it believed had significant public interest simply because it would generate political “heat”. Scott argued sections of News Corp maintained a “deep opposition to public broadcasting” and were “quite obsessed” with the ABC.

The prime minister used an interview with the News Corp and Network Ten commentator Andrew Bolt to criticise the national broadcaster for acting as an "advertising amplifier for the Guardian" by collaborating on the Indonesia spying story.

"I think it's fair enough for people to question the judgment of the ABC, not in failing to cover the story as it were, because plainly it was a story, but in choosing to act as, if you like, an advertising amplifier for the Guardian. It was the Guardian's story which the ABC seemed to want to advertise, even though there's not normally advertising on the ABC,” Abbott said on Ten's Bolt Report.

Asked last week whether he planned to do anything to change the ABC, Abbott told reporters he intended “to speak plainly and candidly with the Australian people in the hope that ABC management will see sense”.