Both lanes of State Highway 1 south of Cambridge have re-opened since a head-on crash earlier today.

Northern fire communications shift manager Jaron Phillips says five people were injured in the 11.24am crash which happened on SH1 near Kentucky Rd, south of the SH29 turn off to Matamata and Tauranga, near Karapiro.

Two of the patients have serious injuries, one has moderate injuries and two others have minor injuries.

The road was initially blocked however emergency services were initially able to re-open one lane.

Advertisement

Waikato police Senior Sergeant Damian Rangitutia has confirmed both lanes were re-opened about 1.30pm and traffic is now flowing freely.

Auckland man Chris Gregory was heading back home along SH1 when he came across the accident.

"I was in a line of traffic about 250m from the incident. I got out of the car and walked down. It appears that the driver in that car was walking and standing, albeit looking a bit dishevelled, with a bit of a blood stain."

Gregory said the driver of the Mazda told him he was allegedly hit by an oncoming vehicle and tried to get out of the way but had no luck.

"He tried to avoid it and the result is what you see [in photo]."

He says traffic still isn't moving and he doesn't expect it to in the near future so he's taken a short cut through Karapiro to get back to Cambridge.

"They obviously hit at quite a pace."

It was the second accident he'd witnessed in the past few days after witnessing one on the northwestern motorway by Western Springs.

"So I'm taking it very easy today."