The Australian War Memorial will defy the federal government's push for paid parking in the Parliamentary Triangle.
However, the memorial will ask the government to pick up the million-dollar tab for major alterations to keep office workers from Civic out of its car park.
The memorial's council has decided unanimously that parking must remain free for veterans, tourists and staff.
The cost to install secure barriers around the car park to deter drivers of soft-roaders forcing their way in could be as high as $1 million.
The Labor government revealed in the last budget that paid parking would be introduced from July next year in four inner Canberra precincts - the Parliamentary Triangle, Barton, Russell and Acton.
Along with Parliament House, the four independent institutions that control their own car parks - the National Gallery, National Portrait Gallery, High Court and War Memorial - face a dilemma: impose paid parking on staff and volunteers or risk having free car parks swamped by public servants.
Memorial director Brendan Nelson said on his arrival at work each morning at 7.15 the car park was filling up.
''Before pay parking has even started, I see people parking here and heading off to go somewhere else to work,'' he told Fairfax Media. ''The risk we have is that if we do nothing, come July next year we will have four-wheel-drives driving over footpaths and people filling up the car parks early in the morning and then our visitors will have nowhere to park.
''In order for us to maintain free parking, it will require us to put barriers up.
''We will obviously have to put boom gates in and validation mechanisms and the architects have told me we will have to widen the entries and exits to car parks. It is quite a significant investment in infrastructure.''
Dr Nelson said the Coalition's veterans' affairs policy argued strongly for the memorial to maintain free parking.
''That is very much my view, that it should be free parking here, but it's not as simple as that.''
Dr Nelson said after paid parking was adopted by the government on the recommendation of the National Capital Authority, the authority wrote to the memorial.
''The NCA said it was willing to provide financial assistance to the memorial in implementing the government's policy,'' he said.
''I have written to the acting CEO of the NCA to say, thank you very much, it's going to cost us a million dollars to implement your policy and we are seeking support from the NCA to implement that policy.''