Neither Labour or National say they used data services like those of Cambridge Analytica - the company embroiled in controversy over its use of 50 million Facebook users' data - in their 2017 election campaigns.
A spokeswoman for Phil Twyford, who was Labour's election campaign chairman, said Labour did not use any data analytical company, while a National spokesman said the party didn't use Cambridge Analytica, and didn't intend to.
Cambridge Analytica has been under pressure over its use of 50 million Facebook users' personal data to build sophisticated profiles, which were then used to target voters in the Donald Trump presidential campaign.
Yesterday Facebook chief Mark Zuckerberg apologised for the "breach of trust" and vowed that Facebook will do better to protect user privacy.
President Trump appeared to brag about using Cambridge Analytica on Twitter: "Remember when they were saying, during the campaign, that Donald Trump is giving great speeches and drawing big crowds, but he is spending much less money and not using social media as well as Crooked Hillary's large and highly sophisticated staff. Well, not saying that anymore!"
NationBuilder was used in both the Remain campaign in the Brexit vote and in Trump's campaign.
But Labour Party general secretary Andrew Kirton said the party did not use Cambridge Analytica or any other external company to crunch its numbers.
"It's overrated and our focus is on real conversations with voters on the doorstep and on the phone."
He said the party used data from sources such as the Census to guess, for example, who was a student and therefore potentially interested in receiving information on its tertiary fees-free policy.
A National Party spokesman said National developed its messaging strategy internally.
"While digital tools are useful, we have found that nothing is as effective as traditional campaign methods of actually getting out and talking with New Zealanders, listening to their aspirations and concerns in person.
"We have used contractors to assist with some content creation and administrative tasks associated with running engaging social media channels. "
The spokesman said the party used Facebook to help maximise its advertising and to target supporters, similar to buying radio or television advertising based on ratings and demographics.
"Targeting tools are helpful to deliver value for money. For example - targeting relevant messages or policy to people who 'like' our Facebook pages, young voters, senior voters, or voters in a particular location."
He said Crosby Textor, which the party has used in previous campaigns, was involved for some polling and research.
The Warehouse Group confirmed earlier this week that it had used Cambridge Analytica services for market research, but a spokesperson said local customer data was not at risk.
Parliament will next week consider the Privacy Bill, which will introduce mandatory reporting of harmful data breaches, and bring in new offences with penalties up to $10,000.
But the bill omits the Privacy Commissioner's recommendation to penalise companies up to $1 million, or individuals up to $100,000, for harmful breaches of privacy.
In the bill's current form, if millions of New Zealand Facebook users' data was breached in a harmful way, the Privacy Commissioner would be mostly powerless to penalise the company as long as Facebook reported the breach.
The commissioner could only fine the company $10,000 as part of a compliance order to fix the problem.
Justice Minister Andrew Little said he expected the bill to be improved after Select Committee scrutiny.