Photo: RNZ / Rebekah Parsons-King
A protest was held in May in the city against the council's decision.
The local Taiwhenua said current laws were in breach of the principles of the Treaty of Waitangi and the Crown's Treaty obligations to ensure Māori had adequate and proportionate representation at a local government level.
The five claimants are from the local iwi authority Te Taiwhenua o te Whanganui ā Orotū - Tamati Cairns, Shayne Walker, Tania Eden, Matthew Mullany, Alayna Hokianga and Hori Reti.
"To date, Māori representation and participation in local government has continued to languish well below the proportion of Māori in the population," the claim read.