A meeting between Jacinda Ardern and Twitter's CEO is being described as hugely significant.

The Prime Minister will on Monday talk with Jack Dorsey about eliminating extremist content online.

Netsafe CEO Martin Cocker expects the discussion to be similar to those his team regularly has with the social media platform.

"We're both against the kind of harmful content that occurred around the Christchurch attacks, but practically getting rid of it is going to be difficult. I'd imagine they're going to have a conversation about the way that they balance free speech against harmful content on the platform."

Ardern and Dorsey last met in Paris for the launch of the Christchurch Call.

Cocker says his team has been speaking with Twitter for some time about removing such harmful sites as 8chan.

"We would absolutely support a call for Twitter to remove the account of 8chan, and other ones like it."

8chan is an internet messageboard with few rules. In recent months, extremists have uploaded manifestos to 8chan immediately before carrying out mass shootings - the alleged Christchurch gunman among them.

The latter also posted warnings of his intentions on Twitter in the days before the massacre, which left 51 dead.

Cocker says the meeting will be hugely significant.

"Not long ago the CEOs of these companies would have ducked and avoided these kinds of meetings."

A spokesperson for Ardern told Newshub the pair will be "continuing discussions on eliminating terrorist content from social media platform".

Twitter has regularly been criticised as having a light touch when it comes to enforcing its own rules against extremism.

Newshub.