Paramedics were called to help police on Wednesday night, after a car pulled in to a booze bus check point with a woman in labor in the front passenger seat.
The Toyota hatch-back back pulled up near the booze bus on Spencer Street in West Melbourne about 6.15pm, surprising traffic police.
The two male police officers from Melbourne Highway Patrol soon noticed the woman was in labor and called paramedics.
The male driver and his 35-year-old female partner, both from Werribee, were taken to St Vincent's Hospital.
The woman was in hospital last night and as of 9pm was yet to deliver the baby.
Earlier this month a woman gave birth to a daughter on the back seat of a car while being chased by police. The new mother Meta Ouk, 25, said her husband ran a red light in Melbourne's south-east and failed to stop for police because she was concerned for her baby's well being.
Police followed the car to Dandenong Hospital. No action was taken against the father for failing to stop.