REDBRIDGE park-and-ride is to be expanded amid new fears about shortages of car parking in Oxford.

Plans to create an enlarged two-deck car park at Redbridge have been hastily put together to serve the city centre once the existing Westgate Centre car park is demolished. But the city will have to cope with significantly fewer car-parking places during the construction of the new £330m Westgate retail centre than had been promised.

Drivers had originally been told 900 car parking spaces would be created to make up for the loss of the city centre's multi-storey car park, which is to be demolished.

It now looks like motorists will have to make do with an extra 250 places on the edge of the city at Redbridge, along with 360 spaces at a temporary car park on Oxpens.

With the starting date approaching, the carefully worked out plans of the Westgate Partnership were thrown into disarray when it was forced to withdraw plans for a second 600-space Oxpens car park.

Councillors supported local residents who said they were unhappy about a two-deck car park being created on recreational land next to Oxford Ice Rink.

Now it seems more people will have to use the park-and-ride, with improved information signage being offered as a sweetener.

The new parking plans for the city will be submitted to the city council's executive board on January 7. The plans set out how the developers hope to minimise disruption to the city during the construction programme, without causing the 2011 completion date to be put back.

Trading pressure group ROX (Rescue Oxford) warned that the reduction in car-parking spaces would seriously hit city-centre traders, resulting in more shoppers heading to Swindon and Reading.

The report to councillors says the developers wanted to create the two Oxpens car parks to allow the new Westgate car park and the John Lewis store to be built simultaneously, saving six months' construction time.

A two-decked Redbridge car park is now seen as the alternative, and would be operational in June 2009.

The report says: "The rationale behind the reduction in the overall number of temporary spaces is that there is likely to be sufficient spare capacity at Redbridge. That capacity, together with appropriate advanced driver information signage, will provide the parking space numbers required."

Councillors will be told some work on the existing Westgate car park will begin next month to prepare for the diversion of a stream and the installation of mains services. Demolition work will follow in February with an archaeological study of the site carried out between March and June.

The need for further archaeological work on the existing car park site has resulted in the construction programme having to be extended to 50 months. The timetable was also hit by an inquiry into compulsory purchase orders being delayed.

Graham Jones, of ROX, said the city had been promised 900 car parking spaces. "Anything less than 900 is just not going to be enough for the city. Oxford city centre is going to be left with an inadequate amount of car parking over many months.

"It will mean the city will lose tourists and visitors. Putting the car parking out to the park-and-ride will not work for many people who want to come into Oxford."

But Susanna Pressel, city councillor for Osney, said she hoped that the new tier at Redbridge could become permanent.

She said: "Money would be much better spent on a permanent solution than a temporary one. We will have to study the environmental implications and listen to residents. But I think this could offer a permanent solution to the problems of congestion and pollution resulting from traffic coming into the city along the Abingdon and Botley Roads."

The Westgate planning application had originally proposed keeping the current car park open, while its replacement was being built.