Concerns about escalating charges at car parks in Cardiff city centre have been raised in the House of Commons.
Prices are said to have more than doubled at one car park
An early day motion, tabled by MP Jenny Willott, urges NCP to reconsider the "extortionate" price rises saying they could deter people coming to the city.
It comes as Cardiff Council outlined plans for a 1,000-space park and ride scheme it says will "avoid congestion".
The Cardiff Central MP said charges had risen by 130% in some car parks. NCP was not available for comment.
"Thriving city centre"
The early day motion highlighted that at the city centre's Wood Street car park, prices had more than doubled from £2.80 for two hours to £6.40.
The prices were unaffordable for people on low incomes, it said, and could have a "detrimental effect" on retailers if people were put off coming in to the city centre.
Ms Willott, a Liberal Democrat MP, said she had visited NCP's London headquarters but had got no further than reception to speak to anyone. She has also written a letter to the company to which she is hoping to get a response.
"There's been some research done by the RAC about the damage done to city centres by exceptionally high parking charges and we have a really thriving city centre in Cardiff and we want to keep it that way" she said.
"By having these huge parking increases, it just means that people on lower incomes are going to be less able to come in to Cardiff and that could affect both their social life and their working life."
The only positive result of the problems might be an increase in the use of park and ride facilities, said Ms Willott.
But she added that city centre parking was needed for people like those with mobility problems.
Meanwhile, plans for a new 1,000-space park-and-ride on the outskirts of Cardiff were put forward.
Cardiff Council hopes that the parking in the Pentwyn and Llanrumney area of the city will be used by shoppers and commuters travelling from the east.
The car park, which would open off the A48 Eastern Avenue by late 2008 or early 2009, would provide secure parking with frequent buses operating to and from the city centre.
Councillor Elgan Morgan said: "Park and ride schemes offer shoppers and commuters access to the city centre which avoids congestion and promotes sustainable transport.
"It will also offer a cheaper option for those who wish to travel by car and stay in the city centre for longer periods."
A 1,000 park-and-ride for those driving in from the west is planned as part of the Cardiff City Football Club's new stadium development.
The council already operates weekend park and ride schemes from Companies House and County Hall, plus seasonal weekday services in the run-up to Christmas.