An off-duty Mountie is being credited with rescuing a two-year-old girl whose mother crashed their car into a water-filled ditch while swerving away from waddling ducks on Highway 17.

Const. Aaron Jabs of the Integrated Homicide Investigation Team was driving by the scene at 7 a.m. Wednesday when he was alerted to the crash by a wet six-year-old boy he saw by the side of road.

Jabs rushed into the ditch, where he saw an overturned car partially submerged in water and the boy's mother Alyse frantically struggling to get her daughter out.

The 25-year-old Surrey mother told police it was dark outside and she couldn't get the car's door open.

"I was so distraught," Alyse said in an RCMP-provided quote. "I couldn't have got my daughter out without him."

The officer managed to rescue the girl with help from his wife, who brought a flashlight-equipped cell phone.

The grateful mother says she didn't learn until after the fact that her toddler's saviour was a policeman.

Jabs says he reacted the way any off-duty officer would have, but his superior Insp. Ward Lymburner issued a statement describing him as an exceptional officer whose "display of humanity here shows an extension of the kind of person he is."

Police said the use of a properly-secured child seat was also crucial to the safe outcome of the crash.

The mother and her children were taken to hospital for treatment of minor injuries and released.