He said a while ago he was given notice of a motorcycle rider being sent to hospital after hitting a large pothole in Kakaramea, between Hāwera and Waverley.
Nixon said the man suffered a fractured vertebrae, cracked ribs and had to have a titanium plate put in his neck after the crash.
That same day a second motorcycle, which was part of the same group, crashed after hitting the same pothole, he said.
Emergency services were also experiencing problems with the conditions of the road.
"A police car was damaged, it had three wheels [damaged], two of them were taken off and one of them was flat, and an ambulance lost a tyre," Nixon said.
He said the ambulance also had its front bumper ripped off by the debris and the crew was shaken up after the incident.
"It's not just Joe Public driving and finding them, it's affecting everyone."
Last winter the region experienced similar issues, Nixon said, with heavy rain causing more potholes to form, for which extensive repairs were undertaken on some roads.
"Most of those have held up all right but we still have got a lot of areas around Eltham where there is certainly a lot of potholes," he said.
Nixon had been out of the region this weekend and said the conditions of the roads were significantly better than the highways in South Taranaki.
He hoped that by sending the letter the forum would be able to open up more discussions with Waka Kotahi and the transport minister.
He would like to see a change in how Waka Kotahi allocated its funding to the region.
"I realise that there are other regions that have issues, but this whole model of effective funding for Waka Kotahi, as far as their capital works and their maintenance works, is totally failing us all," Nixon said.
"We're actually at an unprecedented state with the state of our state highways."
Last week Waka Kotahi told RNZ it had a significant amount of work programmed for State Highway 3 during the upcoming construction season.
Potholes in the region caused by recent heavy rain had been temporarily filled and longer-term repairs would be made when the weather improved.
It said motorists should drive to the conditions and make sure their insurance was up to date to cover any damage that may occur on the road.