The police officer then came across the two crashed cars further down the road.
Mr Clifford said there was no "pursuit'' of the vehicle as the officer did not have time to activate one.
"It all happened very quickly and by the time the officer got on to the state highway from the side road, the offending vehicle was some distance away and soon became out of sight,'' Mr Clifford said.
The police Serious Crash Unit is investigating, and the Independent Police Conduct Authority has been notified due to the involvement of the police vehicle.
Meanwhile, police have released the name of the woman who died after her car left the Hawke's Bay Expressway and crashed into a ditch on Sunday.
She was Hester Raharuhi, 25, of Hastings.
She died at the scene despite the efforts of doctors and a paramedic who came across the scene of the crash just after noon.
Her 2 year-old daughter, who was securely strapped in a seat restraint, escaped with minor to moderate injuries and is in a stable condition in Hawke's Bay Hospital.
- APNZ