UPDATED 5:10am: A woman is in a critical condition in Middlemore Hospital this morning after falling from the boot of a moving car - bound and gagged.

The incident happened just after 7 last night near the corner of Huia and East Tamaki Roads in Papatoetoe.

Local resident Jay Shah was taking out his rubbish when the boot of a passing car popped open and the women fell out.

He said she was barely responsive, gasping for air and bleeding from the nose as he removed a suit tie from around her neck.

Police believe the vehicle involved was a silver sedan.

The woman, believed to be in her late 30s, is in a critical condition in Middlemore Hospital after the incident which occurred just after seven o'clock near the corner of Huia and East Tamaki Road.

The man said he immediately ran to her, but she was barely responsive.

"She could not talk or anything. She was bleeding from her nose, so I thought she was getting strangled, so I started removing the tie from her neck.

"Then I tried to help her out. When she fell she was lying on the ground and that's the way she was the whole time, but she could not move. So I basically thought she was about to die."

LISTEN ABOVE: Witness tells Newstalk ZB's Alicia Burrow what he saw

The incident has sparked a major police operation, and roads in the area are closed.