"We treated one patient in critical condition, and they were taken to the Hawke's Bay Hospital."
Hawke's Bay DHB spokeswoman said the man was transferred to Wellington Hospital for further treatment on Sunday morning.
A spokeswoman for the Wellington Hospital said he was in a serious condition on Monday morning.
A police spokeswoman said on Monday the man allegedly fell out of a moving car.
The other occupant of the car at the time sustained minor injuries.
They had initially left the scene, but then returned and they were now assisting police with enquiries.