Construction of controversial new security fences across the lawns of Parliament House will be under way within weeks after construction equipment and demountable buildings were installed for upgrades on Wednesday.
Traffic around the ministerial entrance at the back of the building was slowed as a large crane lowered equipment behind the existing security fencing while new temporary markings appeared on the nearby lawns.
Plans for new 2.6 metre fences across the sloping lawns and new fortifications around the building were rushed through Parliament as politicians prepared to leave Canberra for Christmas last year, but the exact location, design and cost are yet to be made public.
Parliament's presiding officers, Speaker Tony Smith and Senate President Stephen Parry, have cited national security concerns as a reason not to release information to the public and MPs briefed on the plans have remained tight lipped.
"Site sheds were delivered to Australian Parliament House this morning in preparation for the commencement of the building's planned security upgrades, which are due to commence in the coming weeks," a spokeswoman for the Department of Parliamentary Services said.
The fence is expected to be painted to match existing metal work with its design avoiding horizontal elements intruders could use to scale the barriers.
More than 15 external firms and consultants are being used in the wider security upgrades, including Manteena, Lendlease Building, GMB Architects and THB.
One MP told Fairfax Media the steel fence would be "almost at street level". The fences could be covered with foliage to lessen the visual impact to architect Romaldo Giurgola's original design.
The new fence and other upgrades have been designed by architects Guida Moseley Brown in consultation with officials who worked alongside the Mr Giurgola and the original design team in the 1980s.
The works stem from a September 2014 review of security at Parliament, prompted by the increasing terrorism threat level in Australia, and come after attacks at the Canadian Parliament in October 2014 and at London's Westminster in March.
The plan is supported by the major parties, with the only opposition from the Greens and Victorian independent senator Derryn Hinch.
Greens senator Lee Rhiannon said it was time for the public to see the designs and cost of the fence.
"The presiding officers should now be releasing information about the extent and the look of this so-called security fence," she said.
"Otherwise they're going to look even more foolish because while they're trying to maintain secrecy, there's going to be builders constructing this."
"I strongly dispute the need, I strongly dispute the way the presiding officers have handled this and their justification that the AFP, ASIO and the Attorney-General's Department are supporting the fence. Security is very important but this is looking like a huge overspend and overreach by agencies which have enormous power."
In January the Australian Institute of Architects backed down on its opposition to the security fence, just weeks after its own petition against the controversial plan attracted nearly 4000 signatures.
After saying it was "deeply concerned" by the plans and warning the fence would destroy the character, heritage and symbolism of the Parliament, president Ken Maher and other representatives were invited to a confidential briefing with Department of Parliamentary Services secretary Robert Stefanic.
The institute withdrew its petition and said it was satisfied the fence had been designed in a well-considered manner and would have only minimal visual impact.