Wellington police are looking for a taxi driver after a man was seriously injured falling from a moving cab early on Sunday morning.

The man and two women got into the taxi on central city Courtenay Place about 4.30am.

The taxi stopped shortly after 5am near the Caltex petrol station on State Highway 2 in Upper Hutt, where the man fell out.

Police hoped the nurse and school student costumes worn by the women would help jog witnesses' memories, Upper Hutt Detective Sergeant Richard Orr said.

The women may have been seen getting out of the taxi near the Caltex, shortly before the man came out as the taxi moved off.

Mr Orr said the driver may not have been aware the man had been seriously injured in the fall.

The taxi driver was described as a large male Maori or Polynesian.