Director Nick Mitzevich has called for voluntary redundancies from the gallery's 300-odd ongoing staff as the institution struggles to deal with rising utility costs, building maintenance, falling interest rates and the ongoing efficiency dividend implemented by the federal government.

Mr Mitzevich said though the timing was unfortunate, the cuts were not COVID-related, but the result of several months of discussions on how to cut back.

"We've got rising costs, we've got the efficiency dividend, our ability to raise income is limited, and so all of that needs to be part of a bigger approach," he said.

"We've taken a big hit with interest, and all the money that we get at the beginning of the financial year, we invest it, and what people don't really realise is that as we spend it down, we pull income from the interest. Utility costs and specialist services are also going up."

He said while the gallery had been working with government to deal with the immediate effects of the coronavirus crisis, it was the future consequences that would be harder to address.

"With COVID, 80 per cent of our audience comes from interstate, so in the future, we don't see a bump," he said.

"We don't see ourselves being able to jump back as quickly as, say, the metropolitan institutions can, because it's all about travelling to Canberra."

In a statement in Tuesday, ACT chief minister Andrew Barr said supporting national cultural institutions was vital to Canberra's coronavirus recovery plan.

"These institutions collectively bring hundreds of thousands of visitors to Canberra each year, and the ACT government has proven a track record of significantly supporting them through our Major Events Fund," he said.

"The government has also provided advice to the Commonwealth on ways that the institutions could raise more income and avoid situations where people have to lose their jobs.

"When the Commonwealth can fund $500 million for the redevelopment of the War Memorial, there should not be job losses in other institutions."

Mr Mitzevich said he was dealing with a situation that many institutions faced around the country.

"I just want to be responsible and a focused institution. What I'm trying to do is make sure that excellence and our ability to touch the hearts and minds of as many Australians as possible isn't compromised by this," he said.

While he wouldn't put a figure on how much the gallery needed to save in coming years, he said its workforce of around 300 ongoing staff needed to be reduced by 10 per cent.

"We're asking our staff who would like to leave us, and down the track we'll have to assess how many people put their hands up," he said.

"In these - and I hate to use this cliche - uncertain times, it's unclear how many people might jump to the voluntary program. So down the track we'll move to a targeted program if necessary.

"I'm just trying to be responsive. We're a public entity, we serve the Australian public so I'm trying to make sure that we can continue to serve our mandate and work within the financial envelope we have."

He said the gallery's exhibition program, including travelling shows and especially its popular international blockbusters, wouldn't be affected by the staff and cost cutting, as these were funded externally.

"Those sorts of projects are independently funded - a combination of ticket income, grants and sponsors make sure that those projects are always cost-neutral," he said.

"Our expenditures are always matched by our income, and that's why those big shows always have incomes of tickets, merchandise, cash sponsors, private givers and partners, and so those projects are always cost-neutral because of the way that we fund them.

"What we want to do is make sure that we put the collection to work...I have to be financially prudent as well as artistically adventurous, and it's actually a tightrope.

"Like lots of institutions around the country, we face a very difficult period."

Although he reiterated that the cuts were not entirely down to the federal government's ongoing efficiency dividend, deputy national secretary of the Community and Public Sector Union Beth Vincent-Pietsch took the opportunity to call on the federal government to exempt cultural institutions from the "razor gang".

"Over the last decade, cultural institutions have been starved of funding by this federal government," she said in a statement.

"There is no fat for the gallery to cut, these staff cuts are only cutting into bone. Our members are seriously concerned about the impact these cuts will have on the galleries ability to collect, restore and exhibit in the future."

In a joint statement, shadow public service minister Katy Gallagher and shadows arts minister Tony Burke also called on the government to do more to support the cultural institutions sector.

"Reports that around one in eight jobs at the NGA will be cut is devastating for those who work hard to deliver exciting exhibitions and tell the stories of our nation through art," they said.

"It also comes at a time when galleries around the country are hurting after being abandoned by the Morrison Government during the COVID-19 pandemic.

"Management at the NGA have been forced into this decision due to years of funding cuts imposed by this government.

"The 2014-15 budget delivered cuts to national institutions of $2.4 million and in the 2015-16 MYEFO a further $36.8 million was cut from cultural and collecting entities within the Arts portfolio, Including a cut of nearly $4 million from the NGA.

"With public servants working hard to keep Australians safe it's time the PM gave them his support and guaranteed that there will be no further job losses across the APS as we recover from the COVID-19 pandemic.

"He can start today by protecting the jobs at the NGA."