"Fortunately the New Zealand media landscape has not seen the sorts of hate speech and fake news outlets that have become common in some of our other markets, so in New Zealand the whitelist is fairly comprehensive. However we have taken steps to ensure that digital networks which distribute our advertising to specific international outlets must declare all those websites for our review in order to be included on our whitelist," Williams said.
Vodafone Group chief executive Vittorio Colao said: "Hate speech and fake news threaten to undermine the principles of respect and trust that bind communities together. Vodafone has a strong commitment to diversity and inclusion; we also greatly value the integrity of the democratic processes and institutions that are often the targets of purveyors of fake news. We will not tolerate our brand being associated with this kind of abusive and damaging content."
The company said outlets will not be allowed on its whitelist if their main purpose is to disseminate material intended to degrade women or vulnerable minorities. Satire and opinion will be allowed, but fake news websites that deliberately intend to mislead readers will be excluded.
Vodafone also highlighted that its policy specifically bars any attempt to threaten to withdraw advertising from outlets that criticise the company.
It comes amid growing anger over the placement of major brand advertising alongside YouTube videos posted by Isis supporters and allegations that the video service is facilitating the funding of terrorism, as its contributors receive a share of revenues. Anti-semitic videos on YouTube, which is owned by Google, have run alongside advertising from Land Rover and the insurer Axa.
In March the Government suspended advertising on YouTube after its campaigns were placed alongside extremist videos.
Eric Schmidt, chairman of Google's parent company Alphabet, has admitted that its advertising algorithms and blacklists cannot completely protect brands from extremist material. Google "can't guarantee it but we can get pretty close", he said.
Vodafone has been working on its stricter new approach to extremist material and fake news for eight months, since around the time of the US election.
Debate over the impact of fake news on the unsuccessful Hillary Clinton campaign has raged. Facebook founder Mark Zuckerberg initially dismissed its influence, before introducing new reporting tools to discourage its spread on the social network.
American brands including Kellogg's have blacklisted the controversial right-wing website Breitbart, which has links to the Trump administration and has been accused of championing discrimination and conspiracy theories. Breitbart rejects the allegations.
Commercial concerns are also in play for advertisers seeking to increase the efficiency of their spending. Big brands have registered growing concern abut the effectiveness of online advertising networks, which can spread campaigns across tens of thousands of outlets.
A study in by the US retail bank JP Morgan Chase slashed the number of websites its advertising appeared on from about 400,000 to a whitelist of only about 5000, with no apparent impact on custom.
The ineffectiveness of advertising networks is also understood to have played a role in Vodafone's decision.
The shift will be welcomed by major news publishers, who are likely to receive a boost in income as more brands adopt a whitelisting approach that will divide their budgets across fewer outlets. They will also hope it will mean news publishers get a greater share of online advertising growth. Google and Facebook's dominance has been increasing, threatening efforts to replace declining print revenues.
It follows a potential boost for publishers in the Conservative manifesto, which pledged to ensure "there is a sustainable business model for high-quality media online, to create a level playing field for our media and creative industries".
A Vodafone source said its new policy partly signalled "a return to the old days, where we know the publications that are going to be hosting our brand".
Vodafone's decision was also welcomed in the television industry, which is also seeking to stem the flow of spending to digital players.
Sky chief operating officer Andrew Griffith said: "This just reinforces the return to TV advertising with its enduring strength of being a highly regulated, transparent and brand-safe environment along with the additional benefit of supporting local jobs and paying substantial taxes."
Lindsey Clay, chief executive of the television advertising lobby Thinkbox, added: "Most people don't want to hang out with racists, extremists or liars in the shady corners of dodgy parties. Brands are no different.
"It is good news that brands are taking this issue so seriously and the media industry should welcome Vodafone's move."
