More than six months after it was rubber stamped in secrecy by federal MPs, a 2.6 metre security fence across the lawns of Parliament House is beginning to take shape.

The steel barrier running across the front of the building is part of more than $126 million in security upgrades and fortification works planned for Parliament House, the details and designs of which have been kept secret by Speaker Tony Smith and Senate President Stephen Parry.

Workers installed the first section of a 2.6m high security fence at Parliament House. Credit:Andrew Meares

Security agencies and politicians agreed on the plans in 2016, with Parliament rushing through approval as MPs prepared to leave Canberra for the Christmas break.

The exact location, design and cost of the fence have never been made public.