A car pulled off State Highway 6, south of Havelock, severely injuring two people.
Two people were seriously injured after their car crashed off State Highway 6 in Marlborough.
Emergency services were called for the Okaramio accident about 12.36 pm on Saturday.
A police spokeswoman said the incident involved two adults and two "younger people" in a single vehicle.
In a statement, police said two people were seriously injured.
A Nelson Marlborough Rescue Helicopter spokesman said the crew should take "some patients" to Wellington Hospital on Saturday afternoon.
The spokesman said a second helicopter was sent from Christchurch.
Fire and Emergency New Zealand spokesman Daniel Reilly said two firefighters were dispatched to the site, one from Havelock and one from Renwick, at around 12:35 p.m.
The accident happened halfway between the two cities, he said.
Crews arrived to find a person stuck in a vehicle. Two people were then taken out of the vehicle and delivered to St John for medical care, he said.
"We still have two teams in place helping the police and St John with scene security," he said.
The police major accident unit had been notified and an investigation into the cause of the accident was underway.