The cost of using park and ride services in Bath is to go up from next month, with some tickets increasing by more than twice the rate of inflation.
Operator First insists the increases are "small" and that its services to Odd Down, Lansdown and Newbridge offer good value.
Opposition councillors on Bath and North East Somerset Council fear the rises will deter people from making the move from cars to public transport.
They have also called for more multi-person tickets to be introduced and for better discounted monthly and season tickets.
From April 1, the cost of a weekday return ticket is to go up from £3 to £3.20, a rise of nearly seven per cent, while a ten-journey pass will increase by more than eight per cent from £12 to £13. Weekend return tickets will remain at £2.50 per person.
The current inflation rate is 2.8 per cent.
Conservative transport spokesman Councillor Tim Warren pointed out that the park and ride sites were expanding in size.
"The expansion of the park and rides will already bolster the profits of FirstBus, so the need for these fare increases seems highly questionable.
"Unfortunately, when B&NES signed the new contract to run the park and rides it handed over control of the fares to FirstBus, so it's hardly surprising we're now seeing price rises.
"At the moment, it can work out cheaper for a group of three to drive into Bath and park in the city centre for the day than use the park and ride. This seems to make no sense at all."
The last park and ride fares rise was in 2010, and First points out that it operates a range of weekly and monthly bus deals which can be used on the park and ride network.
A statement from the firm said: "The park and ride offers a sustainable and convenient way for people to get in and out of Bath city centre and it is popular with both commuters and leisure travellers. While fare reviews are always a measure of last resort we would highlight that there hasn't been one on this service for the past three years, making this latest review long overdue. That said, the increases are small and the weekend ticket remains unaffected.
"We would stress that there are a number of good value products that regular travellers can buy to make their journeys cheaper, not least the First Week and First Month tickets which offer unlimited travel for £2.50 or £2.06 a day (respectively). These tickets allow people to hop on and off all First buses in the area as many times as they like, and offer the added benefit of allowing users to take a child with them for free on any First bus (including the park and ride) in the area at weekends. In response to the request for a family ticket on the park and ride service, we would suggest there is no requirement for this at present as up to five children (aged up to 15 years old) can travel for free with each fare paying adult. We are happy to discuss the requirement for other ticket types with the council if they wish to do so."
A council spokesman insisted that control over fares was not entirely handed over to First.
"The contract states that the operator may increase fares, but only annually, in line with inflation in bus industry costs. Fares have been held since September 2010 despite cost increases in the intervening period. An increase of 11.8 per cent would be needed to cover the increases in bus industry costs over those 31 months and the increase proposed by First is well within that."
