This is not a decision the Council should take by itself. It should put the matter to a vote with the next local body elections.
If they wanted to win the vote, what they should propose is that the Independent Maori Statutory Board is replaced with a Maori ward. The latter is at least democratic. The former is not.
UPDATE: The Council has voted not to consult the public on the matter as they are worried the public would make the “wrong” decision. They voted in favour of establishing a Maori Ward, but only if the Government changes the law so they don’t lose one existing seat. Typical – more worried about keeping their own seats.
I can’t see any chance of National changing the law to increase the size of the Auckland Council.