Rescue services have had a busy morning in Christchurch after two separate crashes within ten minutes left State Highway One blocked north and south out of the city.

Fire spokesperson Andrew Norris says traffic's still being delayed after the crashes took place just before and after 7:30.

He says in the first crash a car hit a tree and collided with another vehicle near Templeton.

"When our crews arrived, they assisted with the extrication of one person from a vehicle - that person sustained serious injuries."

Andrew Norris said in the second crash a car transporter truck rolled north of the city, near Cheviot.

The driver has minor injuries.

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