Kāpiti mayor K Gurunathan has appealed to Transport Minister Phil Twyford to step in to make the region's roads safer.

Mayors are pleading for road improvements after two fatal crashes in one day on State Highway 1.

Two people died on Tuesday in two separate crashes, the first at Ōhau, south of Levin, when a car and a ute collided about 4.50pm.

The second person died in Manakau when a car and truck collided just hours later, at 7.10pm.

MURRAY WILSON/STUFF Horowhenua Mayor Michael Feyen is calling on roading officials to take action.

In a joint statement on Wednesday, Horowhenua mayor Michael Feyen and Kāpiti Coast mayor K Gurunathan said the high number of serious motor vehicle crashes in less than two weeks was "totally unacceptable".

READ MORE: Two people dead and several injured after separate crashes south of Levin

Both mayors demanded an effective and immediate response from the NZ Transport Agency before the heavy holiday traffic heads north.

GOOGLE MAPS Two people died in crashes in Horowhenua on Tuesday.

In their statement, they said the two fatalities occurred on sections of highway the agency would claim have had safety improvements carried out in the recent past – at Ōhau and the Waikawa Beach turnoff on the Manakau straight.

Local people believed the Waikawa turnoff was now more dangerous than before, they said.

The mayors were seeking an urgent meeting with roading officials to find a way to make changes before there were more fatalities.

It was not simply a matter of reducing the speed limit, rather it was a case of making physical safety improvements.

"These recent tragic accidents continue the observation of former coroner Philip Comber who noted that, over the past 25 years, the roads had become 'a killing field marked like a battlefield with white crosses'," Gurunathan said.

"I want to appeal directly to Transport Minister Phil Twyford to step in as this systemic killing field scenario is contrary to his Government's stated Government Policy Statement priority on safety.

"People in Ōtaki are vulnerable because they are forced to travel north to Levin and Palmerston North for access to a lot of their services.

"Ōtaki residents rushing to access health services have to negotiate this killing field."

Passengers were seriously injured in both of Tuesday's crashes.

Senior Sergeant Sam Gilpin urged drivers to take responsibility for their driving and the safety of passengers and other road users.

"The actions you take as a driver don't only impact on you, but on all the road users around you, and potentially those road users' families and friends.

"While police are committed to reducing death and injury on our roads, we cannot do it alone.

"If you see any dangerous driving that could put lives at risk, please pull over to a safe spot and call 111."

Drivers who reported dangerous driving were reminded not to use cell phones while driving themselves, Gilpin said.

"Using your phone while on the road could be the difference between life and death.

"Our message to all road users is clear.

"Don't drive distracted, stay within your own lane, buckle up, watch your speed, and never drive under the influence of alcohol, drugs or fatigue."