Police are seeking the driver of a white van who was approached by a man wielding a tyre iron.
The incident happened on near Te Atatu off-ramp of Auckland's Northwestern Motorway about 3.50am yesterday.
The man with the tyre iron has been arrested, but police want to speak to the driver he approached and a witness who was travelling in a 4WD ute.
Both the van and the ute continued west, toward Henderson, police say.
Police urged anyone with information about the incident to call their local station or message the Police Facebook page, quoting event P033307283.