A learner's near miss in a public car park has forced Powys Council to act on a ban against driving schools.
Learners have been able to use public car parks, say the council
Instructors have been told by the council they are breaking the law if they continue to use the authority's car parks for training.
But manoeuvring into parking bays is now part of the driving test and instructors are fighting the ban.
The authority says its regulations have always said its car parks should not be used by learners.
Rob Harper, who runs a driving school in Montgomery, said the nearest car park learners can practice reversing is in Oswestry - 29 miles away.
"This is going to cost the customers money as well as putting on additional mileage," he said.
"All the other car parks in Newtown are privately owned so we can't use them.
"We are certainly being forced out and learner drivers will feel the effects."
He said he feared what would happen in response to the ban would be that parents would take children who are learner pupils to the car parks and they would then get prosecuted.
It takes 45 minutes to get from Newtown to Oswestry
Mr Harper has set up the Mid Wales Driving Instructor Association with 20 others to lobby the council over the issue.
"We will keep fighting it, we hope to get the support of the general public - it's going to cost them more money."
But Powys Council say they are duty-bound to act after the near miss - of which no details are available - at the beginning of March.
A spokesman said: "There has never been a date when the 'ban' came into force.
"Council car parks are run in accordance with the regulations governing car parks, which states that using car parks for this purpose constitutes an offence."
Lembit Opik, MP for Montgomeryshire, has written to Powys Council after being contacted by Mr Harper's association.
"Parking manoeuvres were added to the driving test in order to cut down the accident rate in car parks," said Mr Opik.
"However, if students have nowhere to practice, instructors may have to insist that the bay manoeuvre is dropped.
"I hope common sense will prevail and the council will reconsider its position."
The council says it is sympathetic to the Mid Wales Driving Instructors Association's need to find suitable alternatives to public car parks.
It says offers to find alternatives have been made.
A spokesman for Dyfed-Powys Police said they had no record of the near miss but they believe an anonymous complaint was made to the council.