Secrecy on ASIO site condemned after collapse of glass panels

Workers were evacuated from the area when the danger became clear and no one was injured, but the construction union says the onus is on builders to ensure no further accidents occur.

The Construction, Forestry, Mining and Energy Union maintains it was not told of the accident for days, and claims the secrecy and tight security surrounding the project is hampering its ability to protect workers.

The union's ACT secretary, Dean Hall, said the builder, Lend Lease, was "hiding behind'' ASIO's reputation to deny the union proper access to the site.

''The issue for us is the builder up there has put two things in place,'' he said.

''The first thing being restricting is the right of entry wherever they can, and the second is hiding behind their client ASIO, and the spooks don't speak."

The controversial $589 million headquarters in Canberra was the subject of a serious security breach last March, when a teenager lay unconscious for up to 36 hours after falling 9 metres into the basement of the building site.

ASIO referred questions about the construction mishap to the Department of Finance and Deregulation, which is managing the building process.

A spokeswoman for that department said 19 glass panels, measuring 3.8 metres by 1.7 metres, cracked and disintegrated more than a week ago, falling from the facade above the main entry on Constitution Avenue. She said the panels, which had not yet been permanently fixed to the building, "progressively failed" from about midday on February 24.

"Workers in the vicinity were evacuated before the first panel failed and the area was cordoned off,'' she said. ''No one was injured.''

An investigation was under way into why the panels, costing about $3500 each, had fallen off.

Lend Lease said it was unable to comment.