Australian Competition and Consumer Commission chairman Rod Sims has warned that regulation rather than positive statements of intent will be required to force big technology companies to properly police the content broadcast on their networks, after some of the world's biggest firms signed a pledge to do better.

Mr Sims joined experts in welcoming a "Christchurch Call" statement, announced by New Zealand Prime Minister Jacinda Ardern and French President Emmanuel Macron overnight on Wednesday, in which tech giants including Facebook, Google, Twitter, Amazon and Microsoft said they would increase their efforts to stamp out the circulation of abhorrent material such as the Christchurch terror shootings.