The woman was stabilised in a Wellington Free ambulance before being stretchered to the Life Flight Trust Westpac rescue helicopter.
Life Flight crewman Colin Larsen said she was not conscious during the transport and was transferred to Wellington ED in a critical condition.
A hospital spokesperson said yesterday her condition had been revised to serious but stable.
Carterton chief fire officer Wayne Robinson, who was at the scene with two firetrucks, plus one from Masterton, said it appeared wet conditions had played a part.
"Conditions are obviously a little bit wet, she's come around the corner, lost it a little bit, slid straight into the pole...the car's cut completely in half."
He said by stretching the car they were able to get rescue gear in and get the driver out in 10 minutes.
"It's a new technique, it's being trialled around New Zealand. It really works."
The old system would have taken half an hour, he said.
"It's time critical, it could be the difference between life and death. It certainly saved the day today."
The crash forced traffic to divert down Hughes Line and East Taratahi Rd during the morning. A Tenix crewman on site said they would have to replace the power pole.