If the government thought it could trim the budgets of the ABC and SBS and escape unscathed, it underestimated the public’s willingness to fight for the public broadcasters.

That was the message sent by protesters around Australia at the weekend when they took to the streets to voice their disapproval of the government’s plan to strip $300 million from the ABC and SBS over the next five years.

ABC Managing Director Mark Scott is expected to address staff on Monday to detail up to 500 job losses and cuts to television and radio programs.

About 6000 people rallied in Sydney, Melbourne and Brisbane over the weekend, many carrying placards saying “Save us from the Abattoir” and “Hands off our ABC”. Protests will move to Canberra on Monday, where Clive Palmer is expected to speak.

• Abbott smashes ‘no cuts to ABC’ promise 
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On Saturday, thousands gathered outside Town Hall in Sydney to hear prominent ABC television presenter Quentin Dempster label Communications Minister Malcolm Turnbull “a bullsh*tter”.

Amid speculation that Lateline was to be stripped of its reporting strength and made “lighter”, Mr Dempster told the crowd that “to make it lighter in an age of geopolitical tensions, terror, corruption and inhumanity is laughable”.

In response, Mr Turnbull told Fairfax Media that ABC journalists “who work hard every day to report the news objectively and without partisan bias or self-interest will feel very let down by Quentin Dempster”.

Speaking at the Melbourne rally on Sunday, Opposition Leader Bill Shorten said the cuts were “ripping at the heart” of a vital public institution, and that Australians were rightly angered by the budget cuts in breach of Tony Abbott’s pre-election promise.

“This is not a government of competition – this is a government of censorship,” Mr Shorten said.

“This is a government of savages, ripping at the heart of our national institution.

“They are launching a brutal attack despite promising in the clearest, most unambiguous language, there will be no cuts to the ABC.”

Trade Minister Andrew Robb on Sunday reinforced his party’s line by arguing that the ABC, as a public service, should not be immune from the government’s efforts to wind back the debt.

“The ABC, which has been a protected species for a long time, has to make its share and its contribution,” he told Sky News.

Coalition minister Christopher Pyne, whose seat is in South Australia, had launched a petition to protect an Adelaide ABC studio from closure, while National Party members were saying, “Don’t touch programming in the bush”, Ms Plibersek said.

“I mean these are the people who have supported these cuts and then they want their own patch of turf protected,” she said.

Community and Public Sector Union president Michael Tull said the cuts would affect all aspects at the public broadcaster that people valued.

“Very few parts of the ABC are going to be saved,” he said.

Greens communications spokesman Senator Scott Ludlam said the government had profoundly misjudged the public mood, while Greens Federal MP Adam Bandt said the Prime Minister was feeling pressure over the issue.

“Tony Abbott if you want to relieve the pressure you’re under the answer is as simple as A.B.C. – abide by commitments,” Mr Bandt said ahead of the rally on Sunday.

The crowd was told the budget cuts would amount to 500 ABC staff losing their jobs, and more facing insecure employment via casual or part-time work.

-with agencies