Uber passengers in Sheffield could see fares rocket due to a licensing dispute, say drivers.
Under changes planned by the firm, drivers would only be able to operate within the region where they are licensed from March 14.
Uber drivers say they agree with the move, being made to improve regulation, but argue that the time scale is unreasonable and could leave more than 100 people out of work.
This could send fares in the city soaring for users of the ride-hailing app, they claim, as there will be fewer vehicles available to meet the demand.
Around 60 drivers visited Uber's offices in Neepsend, Sheffield, on Tuesday, where they staged a demonstration outside before meeting bosses from the firm.
Ismail Hersi, who has a London licence, said: "We're happy to get re-licensed in Sheffield but we need more time to do so and save our jobs.
"There are more than 100 Uber drivers in Sheffield who risk being out of work if they can't get a new licence in time.
"It's going to be expensive for the customers because there will be fewer drivers, meaning there will be a big impact on prices."
Taxi and minicab drivers are allowed to operate outside the area where their licence was issued.
But Uber is this month making a major change, meaning drivers will only be allowed to use its app within the region where they got the permit.
That means Uber drivers granted a licence in Sheffield would be able to operate anywhere in Yorkshire but not in other regions.
Uber chose to introduce the measure following talks with local authorities who claimed the way the app works made it harder for them to regulate drivers operating within their area.
The firm claimed the move struck the right balance for drivers, passengers and the cities it serves, but said the change would be kept under review.
A spokeswoman for the company said: "We are supporting drivers who want to get re-licensed in Sheffield and have been in close contact with the council to try to ensure they can do so quickly and efficiently."
Uber's licence was suspended by Sheffield Council in November but was reinstated the following month following talks with the operator.