Emergency services are responding to a rolled truck near Kereru, 42km west of Hastings.
The crash, involving a single truck and trailer, occurred on Kereru Rd about 8.30am on Monday, a police spokesperson said.
The road is "completely blocked", he said.
Two people who suffered moderate injures were taken to Hawke's Bay Hospital, one via a St John ambulance. The male driver in his 50s flown by the Lowe Corporation Rescue Helicopter.
Emergency services also responded to a truck crash on Weber Rd, near Waitahora, 23km southeast from Dannevirke, about 5.50am on Monday.
There were no reported injuries.
Tararua District Council staff were working to clear the road which has been reduced to one lane.