The managers of five government-related funds with more than $90 billion in funds under management say they are adding their weight to callers for multi-national social media owners Facebook, Twitter and Google to take action against the spread of harmful content.

This follows the live-streaming and sharing on social media of the gunman who killed 50 Muslims and wounded another 50 people who had been at prayer in two Christchurch mosques last Friday.

The New Zealand Superannuation Fund, ACC, the Government Superannuation Fund Authority, the National Provident Fund and Kiwi Wealth put out a joint statement saying the social media companies should "fulfil their duty of care to prevent harm to their users and to society," says NZ Super Fund chief executive Matt Whineray in the joint statement.

"We have been profoundly shocked and outraged by the Christchurch terror attacks and their transmission on social media. These companies' social licence to operate has been severely damaged," he says.

"We will be calling on Facebook, Google and Twitter to take more responsibility for what is published on their platforms. They must take action to prevent this sort of material being uploaded and shared on social media. An urgent remedy to this problem is required."

The fund managers' statement follows a similar call to action yesterday from the heads of three major mobile and broadband phone companies, Spark, Vodafone NZ and 2degrees who said they did their best to block the video.

Facebook owns Instagram while Google owns YouTube.

The fund managers are calling on other New Zealand and global investors to join them in engaging with the social media companies.

"We are in the process of contacting other New Zealand and leading global investors, seeking their support for this initiative," Whineray says.

Andrew Bascand, managing director of Harbour Asset Management, which prides itself on adhering to ethical investment principles, says "it's really disgusting" the way social media has developed but that is probably a reflection of society rather than the individual social media companies.

Differing censorship laws in different jurisdictions also need to be taken into account, Bascand says.

Nevertheless, "my sense is these guys have the algorithms already" to block objectionable gambling and pornography.

"The issue starts with each individual and then with a society as a whole."

Investments

• NZSF – Alphabet (Google) $319m, Facebook $164m, Twitter $11m
  • ACC – Alphabet (Google) $120m, Facebook $60m
  • GSF - Alphabet (Google) $21m, Facebook $10m
  • NPF - Alphabet (Google) $4m, Facebook $2m
  • Kiwi Wealth - Alphabet (Google) $70m, Facebook $35m