A spokesman for the Auckland Rescue Helicopter Trust said the woman's car was reportedly rear-ended by one truck and pushed into a truck in front of her.
The Auckland Westpac Rescue Helicopter flew the woman to Auckland City Hospital in a serious condition.
A police spokesperson said the road was is expected to be closed for some time.
The accident happened around 9am.
Motorists are being advised to delay their journey if they planned to use the affected road, or take a longer detour around Sandspit and Sharp Rds.
New Zealand Transport Authority said to expect delays on State Highway 1 through Warkworth due to diversion queues.