Australian internet service providers have been ordered to block eight websites hosting video of the Christchurch terrorist attacks.

In March, shortly after the Christchurch massacre, Australian telecommunications companies and internet providers began proactively blocking websites hosting the video of the Christchurch shooter murdering more than 50 people or the shooter’s manifesto.

A total of 43 websites based on a list provided by Vodafone New Zealand were blocked.

The government praised the internet providers despite the action being in a legally grey area by blocking the sites from access in Australia for people not using virtual private networks (VPNs) or other workarounds.

To avoid legal complications the prime minister, Scott Morrison, asked the e-safety commissioner and the internet providers to develop a protocol for the e-safety commissioner to order the websites to block access to the offending sites.

The order issued on Sunday covers just eight websites, after several stopped hosting the material, or ceased operating, such as 8chan.

The order means the e-safety commissioner will be responsible for monitoring the sites. If they remove the material they can be unblocked. The blocks will be reviewed every six months.

“The remaining rogue websites need only to remove the illegal content to have the block against them lifted,” the e-safety commissioner, Julie Inman Grant, said.

She said each time a site was blocked the agency would assess whether site-blocking powers need to kick in. She said there had not been an incident since Christchurch that had warranted it.

“There is a high threshold, and there is parliamentary oversight, as there should be,” she said.

“The slippery slope argument I keep seeing [is] this is not obscene content or objectionable content [but] it’s clearly illegal. I don’t see any public interest in making this kind of material that is designed to humiliate and to incite further terrorist acts and hatred.”

The communications minister, Paul Fletcher, said the site-blocks were not intended to be a silver bullet.

“We cannot allow this type of horrific material to be used to incite further violence or terrorist acts,” he said.

“Website blocking is not a universal solution to online harms, but it is important that this option be available to the e-safety commissioner in extreme cases such as this.”

Communications Alliance, which represents internet service providers in Australia, welcomed the certainty provided by the direction.

“We are pleased to see the framework that is now in place as a result of constructive collaboration between industry, government and its agencies,” its chief executive, John Stanton, said.

Inman Grant also revealed that under the government’s recently passed abhorrent violent material legislation, the e-safety commissioner has issued four notices to websites for hosting child abuse material. It had successfully got the websites to take down the material.