Pay-and-display machines could be introduced at four free council-owned car parks in Oxford in a bid to crack down on commuter parking.

It is one of a range of options being considered by the city council to deter commuters from parking free at Hinksey Pool; Walton Well Road, by Port Meadow; Bury Knowle House, Headington; and Alexandra Courts, near Summertown.

Another solution could be a ban on parking during rush hours.

The car parks are all next to parks or leisure facilities owned by the council.

The issue was bought to light by Sushilla Dhall, Green city councillor for Carfax, who said charges should be introduced at the Walton Well Road car park "in the interests of justice".

She said: "Any person coming into the city by car is creating more pollution than if they were coming in by bus. It doesn't seem fair that certain people discover these little places and are parking for free.

"I think it should be charged for at the same rate as other car parks in the city as otherwise it can be perceived as cheaper to drive in than to come in by bus or park-and-ride. "

She added that she would like to see money raised from the ticket charges go towards providing better public transport.

Bob Price, the Lord Mayor of Oxford, said there had been a similar problem at the Hinksey pool car park for some time.

He said: "The difficulty is, it is very convenient to park there and walk into the city centre or get a bus.

"We have just about controlled it over the years by locking the barrier at dusk and opening at about 9.30am. It seems to have got worse recently."

He said introducing charges might deter commuters, but could also prevent people from using the park, and the system would be difficult to police.

Mr Price added: "There is no obvious solution other than some kind of time restriction by opening the barrier later and stopping people who use it for commuting.

"The only alternative would be to have a charge at the weekend when you might get more people coming in later for shopping, and make sure people using the pool get a rebate."

Council spokesman Louisa Dean said: "We are looking at all the options of resolving the issues of commuter parking."

A report detailing possible solutions should be completed in the next few months.