Police in Wellington are investigating a complaint against Labour MP Trevor Mallard, after an incident involving a group of cyclists and a motorist on Wednesday morning.
Mr Mallard was cycling with about eight or nine friends when a car reportedly drove through the group in Willis St in the city.
Mr Mallard and the driver exchanged words, before it is claimed the driver swung his bag at the Hutt South MP.
Wellington Area Commander Peter Cowan says the police have received a complaint from the motorist, but inquiries are at a preliminary stage.
He says there appear to be two versions of events, and he intends to speak with Mr Mallard next week.
Frightened - Mallard
Mr Mallard says he was left frightened by the incident, and denies he did anything wrong during his regular Wednesday morning ride in the streets of Wellington.
He says the incident started when a car forced its way through the group of cyclists he was riding with, before cutting him off.
Mr Mallard says a "full and frank" exchange of views followed with the passenger in the car at the lights.
He says a little further on the man waited for him on the side of the road, and swung his bag at him, which connected with his foot.
Mr Mallard says he is still shaky from the incident, which left him frightened rather than grumpy.
Mr Mallard previously pleaded guilty to fighting in a public place, after punching the National MP Tau Henare in the lobby outside Parliament's debating chamber in 2007.