Disturbing footage of the Christchurch terrorist attack has been blocked online to stop the spread of white supremacist propaganda, as Australia is forced to confront encroaching far-right extremism.

Sickeningly, posts on some social media channels have been mocking the victims and celebrating the attack at two mosques last Friday.

Telstra, Optus and Vodafone have temporarily blocked websites that are still hosting video of the shooting deaths of 50 Muslim people.

Daily Stormer, 8chan and 4chan were among the websites blocked by Telstra and Optus when The New Daily tested access on Tuesday.

But not all of the commentary is so explicit, and the attack on Friday has prompted the question of whether hate speech has crept into the mainstream.

“Every time I write an article, I avoid the comments section and I tell my family to avoid them,” Yassir Morsi, a politics lecturer at La Trobe University, told The New Daily.

“Because even in the wake of the Christchurch massacre, you see people egging the government on and regretful he didn’t finish the job.”

Dr Morsi said some of the comments were “basically calling for genocide” and would never be shrugged off in the same way if they were uttered by a person of colour.

Former race discrimination commissioner Tim Soutphommasane, a political theorist at the University of Sydney, said politicians and news media have a role to play in what is acceptable.

“Public debates set the tone for our society and for what people experience every day in their neighbourhoods, workplaces and public places,” Professor Soutphommasane told The New Daily.

“If people believe that they have a green light to vent hate, we should not be surprised to find them venting that hate in public.”

Australian Communications and Media Authority (ACMA) is investigating whether media, including Sky News, breached regulations by broadcasting the alleged Christchurch attacker’s video.

Separately, convicted racist Blair Cottrell and British alt-right extremist Milo Yiannopoulos have both been given uncritical platforms in Australian media.

Following the terror attack, the Greens accused conservatism of stoking racism, prompting a slap down from Home Affairs Minister Peter Dutton.

He claimed the Greens were “just as bad” as Senator Fraser Anning, who blamed Muslim immigration for the white supremacist’s alleged killings.

Professor Soutphommasane said Mr Dutton was “creating a false equivalence between racism and anti-racism”.

“It should be very simple for our political leaders: They should condemn and reject white supremacism and far-right extremism. They should not be creating excuses for political violence and hate. The problem is racism, not anti-racism.”

Julie Nathan, research director at the Executive Council of Australian Jewry (ECAJ) agreed there had been a normalisation of some forms of hate speech and a shrinking of the mainstream.

“The far-right had been galvanising on anti-Islam issues, stopping the mosques, protesting outside halal places,” Ms Nathan told The New Daily.

She said there were complex factors driving the movements, noting the extreme right is not one monolithic group.

But she said the active far-right was focusing on Islam less and beginning to publicly target other groups.

“Depending on who you’re talking about within the far-right – they look at what support and publicity they can get, and how to galvanise people.

“There’s still been a lot of anti-semitism but it hasn’t always come to the fore within these groups. Some of them have kept it quiet as much as they can while they were focusing more on their anti-Muslim activities.”

ECAJ said there were 366 incidents of anti-semitism recorded in Australia in 2018, an increase of 59 per cent.

“Genocide does not begin with killing. It begins with words,” ECAJ said in response to Friday’s attacks.

“It begins with words. Political, community, religious and civil society leaders all have a duty to lead by example, by setting the right tone of discourse from the top.”

Facebook said it was working with governments and the tech industry to “help counter hate speech and the threat of terrorism”.

The platform deleted 1.5 million variants of the clip within 24 hours.

More than 25,200 Reddit users have called for more action after users spread the alleged attacker’s video and documented beliefs, and otherwise supported the white supremacist.