A pregnant woman says she was left sobbing in the rain after police stopped her car and towed it away.
Helen Parry says she was hysterical when the police took her car keys
Helen Parry said North Wales Police wrongly thought she had no insurance on her father's car, and gave her a £200 penalty with six points on her licence.
Clwyd West MP David Jones, who has seen a valid insurance document, is to raise the issue in the Commons.
Ms Parry, 29, of Llandudno, has made an official complaint to the police, who said she could take the case to court.
Student nurse Mrs Parry, who is 20 weeks pregnant, said police officers had stopped her in a roadside check in Deganwy, Conwy, about 2.5 miles (4km) from her home.
The Daily Post newspaper reported that police would not accept she had valid insurance to drive her father's car.
She told the newspaper that police refused to take her back to her home even though she had told them she was pregnant.
She had to phone her mother Maureen Smith about five miles (8km) away in Rhos on Sea to fetch her. She said she was "hysterical" when her car keys were taken away.
"I was getting so cross. They just weren't listening to me," she added.
When her mother arrived, they both watched in disbelief as the car was put on a pick-up truck and taken away.
Mrs Smith later had to pay £105 to get the car back.
David Jones MP said it was an example of how people were having to prove their innocence against the sometimes erroneous word of a computer.
He has written to chief constable Richard Brunstrom seeking an explanation about the treatment of Mrs Parry and the distress caused to her and her parents.
Mr Jones said he wanted to know why Mrs Parry's mother had to pay for the recovery of the family car, which was being used quite legally.
In a statement North Wales Police said an investigation revealed that the data supplied to police forces via the Motor Insurance Bureau by Mrs Parry's insurer, Direct Line, was incorrect.
"This system is owned by the insurance industry. It is not a police system and the police are not responsible for the data," it read.
"The understandable distress caused to Mrs Parry by Direct Line's apparent failure is very much regretted by North Wales Police especially in view of her pregnancy."
Direct Line said that due to a systems error, the information had not uploaded on to the motor insurance database and apologised.
But a spokesman added: "Should any doubt arise over the accuracy of information relating to an insured's policy, as was the case with Mrs Parry, arrangements are in place for the police to be able to call us should any clarification be required."