Prime Minister Jacinda Ardern announced that the Labour party was signing up to the voluntary Facebook Ad Library tool at its caucus retreat last week, and ACT and the Green Party followed suit.
The Facebook Ad Library Report allows voters to see where campaigning money is being spent on Facebook ads, and it was created after the 2016 US election.
These rules are compulsory in the US, UK, Canada and the EU, but not in New Zealand.
Susie Ferguson spoke to Rory Cellan-Jones the BBC's technology correspondent about how the tool had impacted elections in the UK.
