Fares on Norfolk's park and ride services could rise by more than 20pc across the board under plans proposed by the county council.

The introduction of an Oyster card-style pass would see an overhaul of the pricing and passengers paying a premium to travel at peak times, with those not using the smartcard system faced with fare rises of more than 40pc.

Objectors say the increases are unreasonable and could result in people getting back into their cars to save money, but the council's transport chief has pledged to protect the service.

A public consultation is open until July 16 for people to give their views on the proposed fare increases and changes to the ticketing system.

Passengers would be incentivised to pay by smartcard, with an adult return ticket at peak times, currently £2.40, being replaced with an unlimited travel day ticket costing £3 or £3.50 if paid in cash.

Peak fares would apply before 9.30am and between 4pm and 6pm, with the cost of a peak four-week ticket climbing from £41 to £57.50 – up 40pc – and an annual pass from £410 to £500, a rise of 22pc.

Currently up to four children under 16 can travel for free with a paying adult but under the proposals all children over five years old would pay. The fare for concessions would also rise from £1.10 to a cash price of £1.70 – a rise of nearly 55pc – or £1.50 on a smartcard, up 36pc.

Norfolk County Council says that the changes will mean that the most frequent travellers pay less than occasional users, and that the prices are structured to encourage people to use the quicker and more efficient smartcard system.

David Harrison, Norfolk County Council's cabinet member for environment, transport, development and waste, said the proposals were 'a question of realism' and the fare rises were necessary because of budgets being cut elsewhere.

But he added: 'We are very much in favour of keeping the park and ride going, and anything that might impinge upon that would need to be looked at.'

The changes will also see the introduction of a 25pc discount for 16 to 19-year-olds to support them into college and work, but the removal of the cut-price 'cycle and ride' tickets for cyclists, due to the 'small but consistent abuse' of the fare by people claiming it illegitimately, said the council.

Andrew Boswell, the Green party spokesman for transport, said the smartcard system would help to coordinate public transport in the county, but warned that steep fare increases could jeopardise one of the county council's most successful schemes.

'I think that it's really bad news – these sort of increases are just too high and penalise people who are trying to use public transport and stay out of their cars,' he said.

'The Norwich park and ride has been a success story and it's one of the things that, 10 years ago, the council did very well in starting.

'It would be a tragedy if people began moving away from it. I hope the new administration will find ways to protect this service.'

Passenger Jon Sawyer-Stone has used the park and ride service for 11 years to travel from his home near Aylsham to work in Norwich.

Under the plans, the cost of his 10-day ticket would increase from £22 to £27 – a rise of 23pc, which he said would force him back into his car to commute.

'It's cheaper for me to drive my seven-seater estate car into the city and park at work than stay on the park and ride with these price rises,' said the 47-year-old IT manager.

'I know we have to pay going rate, but it just seems unfair to put these prices up this much above inflation.

'I'm a big supporter of the park and ride and feel passionately about it. I've used every single site at one time or another. I think it's an excellent idea but if it's not economical you cannot expect people to use it.'

The smart cards are being paid for by a central government grant, announced in February, and will be introduced on park and ride buses with a view to fitting every bus in the county with the technology by 2015.

You can have your say on the plans by writing to Mrs L Page, Department of Legal Services, Norfolk County Council, County Hall, Martineau Lane, Norwich, NR1 2DH or emailing trafficorders@norfolk.gov.uk by July 16.