The ABC has called for a staff meeting after the federal government cut $83.7 million from the national broadcaster over three years.

Managing Director Michelle Guthrie sent a “frank” email to ABC staff on Tuesday night after the federal budget revealed the national broadcaster’s operational funding would be frozen from July next year until 2022.

Ms Guthrie said she was “disappointed and concerned” that indexation would be frozen.

She said it would compromise the ABC’s ability to meet charter requirements and serve its audiences.

“We will continue to oppose the decision and seek every opportunity to reverse the cuts in the coming months before they take effect.”

A second email, both seen by The New Daily, said Ms Guthrie would address staff on Wednesday to discuss the cuts.

The ABC – which receives about $1 billion in annual funding – will continue to be exempt from the efficiency measures imposed on the public sector.

The $83.7 million savings will go to other areas in the federal communications portfolio and to the budget bottom line.

The other public broadcaster, SBS, has been given $14 million extra over two years, to make up for revenue it lost when laws to ease advertising restrictions failed to pass Federal Parliament.

It will also get $3 million to help develop local film and television content.

Both broadcasters will go through an efficiency review, announced by Communications Minister Mitch Fifield on Tuesday night.

Finance Minister Mathias Cormann defended the funding arrangements Wednesday morning saying the ABC would still receive $3.2 billion over the three years.

“This is effectively equivalent to the efficiency dividend that applies to nearly all other government taxpayer-funded organisations,” he told the ABC.

“Nearly all other government-funded, taxpayer-funded organisations have to find productivity improvements and operation efficiencies.”

Labor leader Bill Shorten said the ABC was one of the “pet hates of the right wing of the Liberal party”.

“Because the ABC occasionally asks questions of the government they’re going to wind back $83 million,” he told the broadcaster.

“This government manages to find tens of millions of dollars for other media outlets.”

Ms Guthrie denounced the review as unnecessary in a statement, given previous programs to scale back.

Senator Fifield said he was confident more efficiencies could be found.

Ms Guthrie said the ABC’s independence and commitment to in-depth analysis and commentary “had never been more valued or trusted by Australian audiences, nor so critical to the challenges facing the nation”.

She said the $83.7 million could not merely be “absorbed by efficiency measures, as the ABC had already achieved significant productivity gains in response to past budget cuts”.

“The ABC is now more important than ever given the impact of overseas players in the local media industry and the critical role the ABC plays as Australia’s most trusted source of news, analysis and investigative journalism,” she said.

“Stable, adequate funding is essential if we are to continue to deliver for Australian audiences.”

The ABC will continue negotiations with the government.

The controversial 2014 budget also included $254 million in cuts to the ABC over five years, announced by then-communications minister Malcolm Turnbull.

Labor shadow communications spokesperson Michelle Rowland said the Prime Minister had “failed the test” to prove his commitment to public broadcasting.

The Media Entertainment and Arts Alliance said it was “difficult not to conclude the new $84 million cut to the ABC is for political reasons”.

“The ABC’s enemies will be very happy tonight,” the union said on Twitter.

-with AAP

Correction: This article has been updated after the ABC corrected its statement. The ABC was of the view that an additional $43 million in funding for quality news and current affairs would not be renewed. The government has since confirmed it has not made a decision on this funding.