Parliament's presiding officers are refusing to consult the public over a new 2.6-metre security fence to surround Parliament House - citing national security concerns - despite growing demands by MPs for the plans to be published before works commence.

A week after the latest fortification plan was rushed through both houses, Speaker Tony Smith and Senate President Stephen Parry said they would not provide information about the exact location of the new "external perimeter" for the southern and northern grassed ramps.

Fairfax Media understands the controversial fences will be covered with foliage to lessen the visual impact to architect Romaldo Giurgola's original design, while one MP said the fence would be "almost at street level", a reference to Parliament Drive, which rings the building.

Some MPs and staff attended slideshow briefings before Parliament rose for the year, but were not given documents or allowed to take notes.