The editor-in-chief of Quadrant magazine, Keith Windschuttle, has apologised to the ABC's managing director over an article suggesting the Manchester bombing should have instead taken place at the national broadcaster's Sydney headquarters.

In his letter, sent on Wednesday, Mr Windschuttle said the article "represents a serious error of judgement and should not have been published", and said he had "instructed that the article and its comment should be withdrawn completely from our website".

But the article was not removed until mid-morning on Thursday, more than 12 hours after Mr Windschuttle's apology.

A phone screengrab shows the Quadrant article online at 11:57pm. ( ABC News )

ABC boss Michelle Guthrie had demanded the apology, and that the article be removed, in a letter to Quadrant on Wednesday morning.

She condemned what she said was a "vicious and offensive" online journal article.

The article, published on Tuesday night by Quadrant digital editor Roger Franklin said, "had there been a shred of justice, that blast would have detonated in an Ultimo TV studio".

"This morning, mere hours after (Q&A host Tony) Jones' guests pocketed their ABC taxi vouchers and repaired to hotel rooms paid for with taxpayer dollars processed through the Sydney Writers Festival, mere children were torn to pieces on the other side of the world," he wrote.

"Unlike those young girls in Manchester, their lives snuffed out before they could begin, none of the panel's likely casualties would have represented the slightest reduction in humanity's intelligence, decency, empathy or honesty."

ABC staff appear to have been blocked from accessing the Quadrant website. ( ABC News )

After a severe backlash on social media to Franklin's article, the wording was changed to "what if that blast had detonated in an Ultimo TV studio?".

In her letter, Ms Guthrie wrote "Quadrant promotes itself as 'the leading general intellectual journal of ideas'".

"Those words ring hollow in the wake of last night's vicious and offensive attack on the ABC, its staff and its program guests," she said.

She dismissed the article's editorial changes, saying it had "done little to undo the damage".

"I am appalled at your willingness to turn an act of terrorism in the United Kingdom into a means of making a political point against those you disagree with," Ms Guthrie wrote.

She said the ABC was forced to reassure worried staff, "working long hours to provide extensive coverage of this unfolding [Manchester] tragedy".

The ABC has called in security experts to assess any possible impact flowing from the "inflammatory words", Ms Guthrie said.

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Communications Minister Mitch Fifield said the article was a "new low" in Australian public debate, labelling the comments "sick and unhinged".

In an interview on The Drum Wednesday evening, Quadrant board member Nick Cater said Franklin had been "counselled" over the incident.

He would not reveal if Franklin would lose his job over the matter, instead saying "watch this space".

"It would be inappropriate for me to make comments like that as the board member about the future of a staff member of Quadrant," he said.

"I shall make my views clearly known when the board meets, which I hope will be soon, and I have already made those views made to the editor."

He said he would question Mr Windschuttle over the process leading to the article being published.

"What I will be asking Keith to look at, as the editor, is why somebody can write a comment piece and then stick it straight online with no checks and balances, because it is one thing if it is your own blog but this is the website of a magazine that's been going since 1956," he said.

"You put all that reputation at risk just with one piece. I can't begin do go into how disgraceful I think the comments were."

The Australian Federal Police have been notified of the article.