A witness to the crash which killed one person near Hunterville this morning has described swerving off the road along with another vehicle.
Emergency services were called to the scene between Jeffersons Line and Te Houhou Rd at about 9.45am after two cars and a truck were involved in a crash.
Zody Takurua was driving along State Highway 1 on his way to a job interview when he witnessed the accident.
When the vehicles collided, Takurua and the driver of a black SUV were forced to take evasive action.
"Both myself and the SUV swerved off the road. The SUV sustained major damage and I received a flat tyre," Takurua said.
"I didn't receive any injuries and managed to control the car. The family in the SUV were distressed and lots of commotion was occurring."
Takarua said a truck involved did not tip over and he believes the driver exited it safely.
As a result of the crash two cars ended up in a ditch on the side of the highway and the truck took out a power pole before stopping in a paddock.
The Serious Crash Unit examined the scene and for a time light vehicles were diverted around Jeffersons Line, Leedstown Rd and Mt Curl Rd.
Heavy vehicles up to 50 tonnes were forced to use SH4 between Whanganui and Raetihi while there were significant delays for even larger vehicles.
Takurua said the numerous police officers, firefighters and civilians that were involved should be thanked, especially local emergency responder Richard Swainson.
"This really showed how Kiwis come together to help each other out. I'm sure those simple acts of human kindness went a long way to all involved," Takurua said.
"My condolences go to the family of the person who passed away and whilst grave, it is a stark reminder of promoting safe driving on our roads."
Whanganui's acting sergeant for road policing Trevor Scarrow is urging motorists to drive to the conditions and stay within their lane after three fatal crashes in the region in four days.
"Obviously the crashes themselves are still under investigation and that will take some time to complete," Scarrow said.
While he could not comment on specifics, Scarrow said Sunday's crash on SH4 at Kakatahi occurred in atrocious weather conditions.
Crashes on SH3 at Waitotara on Tuesday and SH1 at Hunterville on Wednesday both involved a vehicle crossing the centre line and resulted in cars and trucks colliding. One person died in each of the crashes.
"Our thoughts go out to the families and loved ones," Scarrow said.
"Dealing with serious and fatal crashes also takes a toll on our staff and other first responders.
"We ask the public to please drive to the conditions and stay within your own lane. Always pull over to deal with distractions or to answer your phone."
No other injuries were reported.