Three people killed in a crash on State Highway 1 in Horowhenua on Tuesday afternoon were staff members at a New Plymouth intermediate school returning from the anti-vaccine mandate protests in Wellington, the NZ Herald reports.
Emergency services were called to the crash near Kuku south of Levin just after 3pm on Tuesday, after a truck and van collided.
Police confirmed on Wednesday morning four people died in the collision.
In a statement to Newshub, Devon Intermediate principal Jenny Gellen said the school was shocked and saddened that its caretaker, a teacher and a teacher aide had died in the crash.
"We are extremely shocked and saddened to announce that three of our staff members passed away yesterday in a crash near Levin," Gellen said on Wednesday.
"Our thoughts prayers and love go out to their families and friends during this tragic time. We have the MoE (Ministry of Education) traumatic Incident team on site to help support our tamariki and staff and thank you for your support at this time."
An investigation into the cause of the crash is ongoing. The next of kin of those involved had been contacted, police said in a statement.
"Police would like to hear from any witnesses that may have information that could assist our enquiries.
"In particular, we'd like to hear from anyone who was travelling on the road at that time of the crash that may have dash cam footage," the statement read.
The New Zealand Transport Agency - Waka Kotahi (NZTA) said it would also carry out an investigation.
"Our thoughts and deepest sympathies go out to the loved ones of the people who lost their lives, and to anyone else affected by this tragic incident," NZTA regional relationships director Linda Stewart said.
"We are unable to comment specifically on the crash until these investigations are complete.
"A new four-lane highway from Ōtaki to north of Levin will dramatically improve safety for people travelling on SH1.
"Construction is planned to start in 2025 and in the meantime Waka Kotahi has planned a number of safety improvements for this stretch of SH1, including wide centrelines, stretches of side barriers and a review of speeds to ensure they’re safe and appropriate."
Stewart said improving safety on New Zealand's roads was the agency's top priority.
Anyone with information on the crash is urged to contact police on 105, quoting file number 211109/3758.
