Whanganui MP Chester Borrows, described by the PM as "a very gentle person", faces a police probe after allegedly running over a woman's foot at a Trans Pacific Partnership protest.

Police did not name Borrows, a former policeman, but said they were aware of an incident that occurred at a protest in Whanganui on Tuesday.

"One protester received a leg injury after allegedly coming into contact with a vehicle. Police are currently establishing further information about this to assess what, if any further steps are required from a police perspective.

"This will include speaking to those with relevant information about what happened. As is standard, we do not discuss specific individuals."

A video of the incident shows Borrows' car moving slowly forward, but it does not appear to completely stop, as two police move in and then the protesters move apart.

As the car pulls away one woman can be seen holding her foot off the ground.

Borrows told Stuff he was driving the car, in which Social Housing Minister Paula Bennett was a passenger, but said he was not aware of anyone getting hurt.

"When I went to drive out they were around the driveway exit onto the street and they moved to stand in front of the car as I approached, waited for the police to pull them out of the road and drove off." Borrows said.

He said he was completely unaware there was an incident until he saw it on Facebook.

He had looked at the video posted online.

"The police have told me she has been to the hospital, been X-rayed, no broken bones but some what they call tissue damage."

He said he accepted it may be a possibility he ran over her foot, but he had no idea that had happened.

"I am pleased to hear that she is not suffering."

He had called the police and he expected them to talk to him again because a complaint had been laid. He would be happy to talk to them.

"As far as I am concerned I inched forward, they put themselves in that situation. There was absolutely nobody there in front of the car when I drive away," he said.

Borrows and Bennett were leaving a breakfast meeting with business and local government members when the incident occurred.

The Wanganui Chronicle newspaper reported protester Tracy Treadwell was taken to hospital by St John Ambulance and Whanganui TPPA Action Group spokeswoman Denise Lockett said Treadwell's foot was badly bruised.

Lockett said she was disappointed that Borrows did not allow time for protesters to move out of the way.

Prime Minister John Key said Borrows was "a very gentle person".

"I think they were going incredibly slowly and just trying to move out, and whether someone got in the way of the car, I don't really know - as I say, I haven't seen the video.

"What I know about Chester is he's a very gentle person, he's not the sort of person that goes seeking controversy or certainly not a person known for doing angry things."