A man is under police guard in hospital after crashing his vehicle twice and taking off from police before crashing 70km away. 

Police were first told of a crash about 9.15pm on Atkinson Ave in Otahuhu, where one of the drivers assaulted the other motorist. 

He then took the other vehicle and drove off at speed. 

"Police did not pursue this vehicle but continued to monitor its whereabouts as it continued to drive north in a dangerous manner," a police spokesperson said. 

"Police successfully deployed spikes near Warkworth with the vehicle continuing on. Police were not pursuing the vehicle." 

The man eventually lost control of his vehicle and crashed into a pole in the Warkworth area. 

The driver was seriously injured and taken to Auckland City Hospital where he remains under police guard. 

Charges are likely to be laid, the spokesperson said.