The Auditor-General plans to review vote-counting processes for future elections after the Electoral Commission found errors at several booth locations.
John Ryan's review comes after the commission found multiple counting errors after the election, including more than 700 votes being missed from the final count due to data entry errors in 15 voting places.
The Electoral Commission also found hundreds of votes were allocated to different parties incorrectly.
Auditor-General Ryan on Tuesday announced his decision to carry out a review.
"Although these errors had no effect on the outcome of the results of the election or the result in any individual electorate, the commission had expected its quality assurance processes to have identified and corrected those errors before the official count was completed," the Controller and Auditor-General's office said in a statement.
"It is important that the commission is able to have confidence that the errors it has identified will not re-occur in future elections. Avoiding these errors in future is also important for the public's trust in the vote counting process."
Now-Prime Minister Christopher Luxon last month acknowledged his own frustration at the errors but said he still had confidence in the Electoral Commission.
"I think there are a lot of good questions, to be honest, after a Government is formed about the Electoral Commission and what we learnt from this experience," Luxon told reporters.
"After every election, we take a deep review, all parties get to input into it and I think that's an important process.
"I think there are some genuinely big questions that we could ask in this review as well."
In an interview with AM in November, chief electoral officer Karl Le Quesne said people could rest assured voting was fair.
"We are getting an independent review done of our quality assurance processes to make sure that we can strengthen those."
