He added that, if such an attack took place, "none of the panel's likely casualties would have represented the slightest reduction in humanity's intelligence, decency, empathy or honesty".

The piece, written by Quadrant's online editor, Roger Franklin, was posted on Tuesday night as coverage continued of the terrorist attack in Manchester that has so far killed 22.

The contentious passage was later amended to begin: "What if that blast had detonated in an Ultimo TV studio?" and it remains on the journal's site, entitled "The Manchester Bomber's ABC Pals".

The ABC's managing director, Michelle Guthrie, has written a letter of complaint to Quadrant, describing Franklin's piece as vicious and offensive.

"To take issue with our programming and our content is one thing," she wrote. "But to express the wish that, if there were any justice, the horrific terrorist bombing in Manchester would have taken place in the ABC's Ultimo studio and killed those assembled there is a new low in Australian public debate."

She said that a result of the piece was that, while ABC staff in Sydney and Manchester worked to cover the bombing, management was forced to call in security experts to assess any possible threat to their safety.

She asked that the piece be removed and an apology made.

Minister for Communications Mitch Fifield has described the comments as "sick and unhinged".

A senior staff member at the ABC said it was sickening that an editor at Quadrant would "appropriate the tragedy in Manchester to use in some sort of hate campaign against the ABC".

Because the ABC's Q&A program regularly invites prominent guests to interact with members of the public, it maintains a relationship with the federal police.

Fairfax Media understands that the federal police have been notified about Franklin's comments.

Security is expected to be particularly tight during the program's next episode, which is to be held at Parliament House.

Franklin told Fairfax Media that he stood by the point he was seeking to illustrate in the essay, which he said he had first posted in draft form and updated progressively over the evening.

"The whole piece was an attack on terrorism. It is absurd to suggest that in the third-last paragraph I would advocate a terrorist act."

He said he was making a rhetorical point about the absurdity of a suggestion by one of the panelists on Monday night's program that accidents involving refrigerators kill more people than terrorism, and what he saw as the ongoing refusal of ABC commentators to acknowledge the true causes of terrorism.

"Our lives and the way we live are being constricted, we live in fear and the causes are being obfuscated," he said.

On Wednesday morning, a note was sent out to ABC staff saying comments had been made that constituted "veiled threats" against the ABC's Ultimo premises and had caused concern to some staff.

"ABC takes all threats against staff seriously and pro-active steps have been taken to ensure the safety and welfare of all staff and users of ABC Ultimo.

"While consideration is given to minimise inconvenience please appreciate that intermittent increased security presence and more rigorous security screening is to ensure staff safety and well-being," the note said.

Asked to comment, Quadrant editor and prominent historian Keith Windschuttle, a former ABC board member, told Fairfax Media: "You're talking bulls---, don't call back."