Mana Movement leader Hone Harawira says Māori and Pacific Islanders will be the most hurt by the move to give tasers to frontline police officers to carry while on duty.
Police statistics show one third of the occasions when police discharged or presented tasers last year involved Māori, one third Pacific Islanders and one third Pakeha.
Mr Harawira said the decision had been made out of fear of police officers being hurt and he also wanted police to feel safe.
But he said that should not come at the expense of Māori.
He said he was worried tasers would now become a weapon of first choice rather than a weapon of last resort.
"If you've got the big stick you go, waste of time talking to these people, I'll just pull my taser. That's what I'm opposed to, because I know that the people who are going to be brutalised by this are Māori and Pacific Islanders," he said.
Mr Harawira said he hoped efforts would be made to recall tasers soon.
The police said tasers were used in response to people's behaviour and the risk to the public, not in response to people's ethnicity.