News director Gaven Morris has hit back at the three-year funding freeze announced in the federal budget, which maintains more than $1 billion a year for the broadcaster.

"Make no mistake, there is no more fat to cut at the ABC. Any more cuts to the ABC cut into the muscle of the organisation," he told the Melbourne Press Club on Thursday.

The latest move comes on top of about $254 million in efficiency savings and cuts over several years, Mr Morris said.

Only about four per cent of the overall budget went to back office and overhead costs, he added.

"We're as efficient as we've ever been," Mr Morris said, adding the ABC was the country's most "minutely scrutinised" media organisation.

He declined to go into detail about how many job cuts would result from the funding freeze.

"Eighty-four million dollars over three years, there is simply no way we can achieve that without looking at content creation and certainly looking at jobs within the organisation," Mr Morris said.

"A lot can happen between now and the middle of 2019, including a conversation with the government around a triennial funding submission (for 2019-2022)."

The news director also acknowledged recent "reputational angst" over "one or two stories" the ABC didn't quite get right, without offering further details.

"We take that really to heart, we take that very seriously. And those sorts of risks, we cannot take."

But he urged his journalists to be "brave" in their reporting.

"If a politician is mad with you because you've done a story and you've touched a nerve, most of the time that's because you've told a story that was worth telling," Mr Morris said.

"Don't be afraid of the pressure that will often come to bear on you, even though sometimes people can see that ... as then manifesting itself in a budget cut or reduction or resources or any of those sorts of things."

Earlier, federal Finance Minister Mathias Cormann said the ABC funding freeze was "effectively equivalent to the efficiency dividend that applies to nearly all other government taxpayer-funded organisations".

But Opposition Leader Bill Shorten said the coalition cut the ABC's funding because the broadcaster was one of "the pet hates of the right wing of the Liberal Party".

Australian Associated Press