The ghostface, made popular by the Scream horror movies, was installed by the managers of Mooseheads to celebrate Halloween and to lighten up the building which is still recovering for a devastating fire in February.

"The ghostface has been continually blown up all week although he was taken down during the bad weather," said a Mooseheads manager.

"Some people might say it's stupid but it's just a bit of fun and sometimes it's nice to be a bit light-hearted about these things."

The Mooseheads manager said the inflatable ghostface was "a bit of fun" and no one had complained to staff about being scared or concerned.

While the ghostface may startle those who do not expect to see it peering down on the street, staff hope it will revitalise interest in the venue and surrounding businesses.

"I don't know if we would have been so brazen to do this if we didn't have the other side of the road to contend with," she said.

"With the Sydney Building on the other side, we're trying to show people that we're still alive and kicking over here."

"We have to be brazen at the moment and we need people to know we are here, having fun, and there is future for the Sydney Building."

Canberra CBD chief executive Jane Easthope said sometimes it was nice to be surprised and new initiatives were welcome at the Sydney Building although she had some reservations about the knife held by the ghostface.

The Mooseheads manager said she didn't believe the inflatable figure was any more unsightly than the corner of the Sydney Building which is still recovering from the fire.