In a letter to staff, the gallery's deputy director Kirsten Paisley said a number of vacant positions would not be publicly advertised, with management considering further savings measures.

The letter to staff obtained by Fairfax Media, comes a day after the National Library of Australia detailed a major review of services with key programs to be curtailed or cancelled amid staff cuts.

The major restructure, which includes more than 20 job losses by June 30 and a reduction of international print and online subscriptions, was condemned by Labor and the Greens on Tuesday morning.

"The [Gallery's] executive team are continuing to explore options for the 2016/17 budget reduction target and the budget process will be communicated in March," Ms Paisley said.

"However, budget managers should anticipate a 5 per cent operating cut to be applied across the board and begin discussing with their teams what options are available for achieving a reduced target."

Ms Paisley said vacant positions at the gallery were under review and "for a number we will not be proceeding with recruitment".

On Tuesday, ACT Liberal senator Zed Seselja called for the efficiency dividend to be abandoned, breaking ranks with his federal colleagues.

"27 years of efficiency dividends from both sides of politics can't help but have an impact," he said."It is time that these blunt efficiency dividends were no longer used, particularly for small agencies."

Opposition arts spokesman Mark Dreyfus described the cuts to cultural institutions as a disgrace and called on the federal government to reconsider its position.

In a letter to staff, National Library director-general Anne-Marie Schwirtlich said management needed to find $4.4 million of savings by the end of the 2017-18 financial year including the $1.5 million of savings required by the Mid-Year Economic and Fiscal Outlook Statement.

She said the saving measures would have "a grave impact" on the library and warned staff that management would cease aggregating some Trove content unless fully funded to do so.

All public education programs are currently under review with management ceasing publication of the quarterly National Library of Australia magazine.

The library's corporate management group has also raised the prospect of outsourcing some duties and further automation of collection services.

"As the institution which keeps all publications released in Australia, the National Library is one of our most vital cultural institutions," Mr Dreyfus said.

"Not only does it serve the purpose of collecting texts, it also makes reams of information easily accessible for academics, students, researchers and average Australians interested in their history."

ACT Senator Katy Gallagher said the federal government had pretended to be a friend of the arts while continuing to cut funding for cultural institutions.

"Canberra has suffered more than enough under this government and the cuts to jobs must stop," she said.

"These cuts are not just a savings line in a budget - these are real people who will lose their jobs thanks to this government and their total disregard for the role Canberra plays as the nation's capital."

ACT Chief Minister Andrew Barr said he was frustrated by the cuts and was concerned they would have an impact on the local economy.

"I am extremely concerned about the impact of these cuts to the ACT's tourism sector," he said.

"The national cultural institutions, such as the National Library, are a key part of our tourism offerings. We are doing everything we can to support the tourism industry but these cuts always makes the task more and more difficult."

Opposition leader Jeremy Hanson said he did not support any cuts to Canberra's cultural institutions or other areas of the public service.

"Our national institutions make a huge contribution to Canberra economically, culturally and socially and their importance needs to be recognised and valued," he said.

"I have had numerous conversations with my federal colleagues to express my view and will continue to do so."

ACT Greens senate candidate Christina Hobbs said the National Library was the first institution to reveal the extent of job losses, with many other institutions considering cuts.

"This uncertainty must be difficult for staff who are being forced to watch all of this play out in the media," she said.

"[This] leak is just the latest in a series of reports about cuts, privatisation and outsourcing from a government that has shown disdain for the public service."