The taxi industry is calling for greater protection for its drivers after a cab driver was stabbed in the back after picking up three women in Melbourne's north.

The man picked up the trio after they booked a fare from Sydney Crescent, Lalor, just after 2.30am on Wednesday morning.

A fight broke out after a woman refused to pay their fare and the driver was assaulted and stabbed.

The driver, a 35-year-old Thomastown man, was taken to hospital with non-life threatening injuries.

Australian Taxi Industry Association chief executive Blair Davies said safety regulation had been wound-back over recent years and that proven deterrents such as security cameras had lost mandatory status.