But the law allows deviation greater than 10 per cent if changing the boundaries would split a community of interest, or join together communities that don't share a common interest.
The council's boundary setting meant Te Tai Tonga Māori ward had 16.2 per cent more people than the "average" ward, while Te Kūrae ward had 15.8 per cent fewer people.
Similarly, Taranaki Coastal general ward had 18.6 per cent more people than average and Pātea ward was 27.3 per cent below.
There were no local objections to the council's final decisions in October, but the population discrepancies meant the commission ran a compulsory ruler over the wards.
Although both Māori wards were outside the 10 per cent requirement, the commission's decision noted the boundary between them was based on tribal affiliations.
"The boundary between the Māori wards was defined by Ngāruahine and Ngāti Ruanui in relation to the Te Kūrae Māori ward, and by Ngāti Ruanui and Ngā Rauru Kītahi for the Te Tai Tonga Māori ward, as reflecting the rohe of those iwis."
The commission had already considered the Pātea ward in 2019, and restated its finding that moving boundaries to fit the 10 per cent rule "would result in the grouping together of areas with no community of interest".
"People in the Pātea ward have a strong historical association with the current Pātea ward boundary as this was the previous Pātea District Council boundary, and prior to that the Pātea County Council boundary."
The commission found a cut from three to two councillors in the Taranaki Coastal ward did not provide "fair representation" according to the 10 per cent rule.
But it found "that non-compliance for the Taranaki Coastal Ward is justified to reflect the council's conclusion that the ward comprises geographically distinct communities".
Local Democracy Reporting is Public Interest Journalism funded through NZ On Air
