The predicted cost of repairing Oxford's crumbling bus station has almost doubled.

At first, city councillors were told that Gloucester Green bus station could be repaired for £90,000 but now they are being warned that the cash-strapped authority faces a £169,000 bill.

The bus station needs urgent repairs, as heavy three-axle buses have caused the surface to weaken, threatening the roof of the underground car park.

Last year, it was revealed that concrete blocks, laid in the late 1980s, had started to slide sideways.

Emergency repairs have already been carried out but John Hill, director of community services, warned: "Delaying the repairs to January 2002 is likely to incur additional costs of £1,000 per month."

It is the latest blow for the city council, after pushing through about £3.7m of cuts.

Cllr Jean Fooks, chairman of the highways committee, said: "This sounds rather a large amount and it is clear that the figure we were first given was not accurate.

"We will try to trim costs wherever we can, to see if we can do this more cheaply but that might not be possible.

"We must prevent water damaging the car park underneath. Delaying this has cost implications but the traders won't want the work done before Christmas."

The news follows the revelation that expensive paving was damaged in Magdalen Street, outside the new Debenhams store, and that foundations in Cornmarket Street could limit the extent of a repaving scheme.

At a meeting of the highways and traffic committee tomorrow, councillors are being asked to decide whether to close the bus station for about four weeks in September, or delay the move until January next year.

Highways officers have been considering moving buses to historic St Giles and the Worcester Street car park.

The alternative is using Oxpens coach park, with a shuttle service running back to Gloucester Green, to make sure passengers are dropped off as close to the city centre as possible.

If the Oxpens option is used there will be drop-off points in New Road for London services and services to the south and west of Oxford, and also Magdalen Street, George Street or Beaumont Street for Midlands services and north of the city.

Either option will contribute about £60,000 to the total cost. The shuttle service will cost about £60,000 but the loss of parking fees in St Giles and Worcester Street will come to the same amount.

Councillors will also be told about draft proposals to reduce the number of services using the bus station.

Mr Hill warned: "At times, there can be as many as 34 departures per hour, with more than one third being on local routes.

"Most of the safety hazards are created by the need for manoeuvring by buses between layovers and bays, and vehicles dropping off passengers in the layover bays and outside the 13 designated bays."

Proposals have been put to bus companies to reduce the number of departures to about 20 an hour but so far there has been "very little response".