The police fired a Taser stun gun at a man in West Auckland on Saturday.
Officers say the weapon was deployed when they were threatened with a screwdriver.
The incident escalated when the man was stopped for a minor traffic matter and a police sergeant was assaulted.
The suspect drove off but officers caught up with him; they say they fired the Taser when the man was aggressive and would not co-operate.
A 26-year-old Northland man will appear in the Waitakere District Court on Monday on a number of charges.
