Car tyres and rims are falling victim to a giant pothole that has opened up on State Highway 5 between Napier and Taupō.

The road has been plagued with issues this year after being severely damaged during Cyclone Gabrielle, with more heavy rain slowing repairs.

A man living just down the road from the pothole in Te Haroto told RNZ he was helping motorists put on spare tyres from about 9pm on Thursday until 1.30am Friday.

Triden Harris-Bush says there were about six holes within 100 metres on both sides of the road, and the worst was more than a metre long and half a metre wide and 25mm deep.

"So far I've seen eight broken rims, and that's just from the ones I was able to help," says Triden.

Cars were pulling into his driveway last night after hitting the pothole, so Triden went out to assist.

"I've hit it in my four-wheel-drive and had been chucked around. They filled the hole a month ago and since then it's all come out and got worse."

While speaking with RNZ Friday afternoon, Triden was helping a couple who had two tyres damaged, but only one spare, so were forced to call a tow truck - which was two hours away.

"They're not happy, I've invited them in my home for lunch."

The pothole on State Highway 5. Photo: Supplied / Triden Harris-Bush.

Waka Kotahi says it was aware of the damage to the road, and had asked contractors to undertake repairs as quickly as possible.

'The worst I've ever seen it."

Byron Duncan, the owner of Tiger Tyres in Napier, says he had repaired five tyres and rims on Friday alone for customers who had hit potholes on State Highway 5.

He says the damage was bad, and customers were telling him they had also ruined the suspension, wheel alignment and brakes.

"They're all saying they don't see them, they don't even see the hole until they hit it.

"And then bang, you know, like huge bang, and the holes are really deep.

"The holes are so big they're smashing the rims."

Byron says he had been in the industry more than a decade, and the last few months was the worst he had ever seen.

Staff at other tyre repair shops in the region had told him the same, and had also seen a big uptick in customers needing repairs after hitting potholes.

"It's just never been this bad, ever."

While it was good for business, Byron says he felt for those using the road.

"You've got to feel sorry for some people, some people have got insurance but other people just can't afford it."

Lauren Crimp/RNZ