The public inquiry into the £700m Tithebarn retail scheme in Preston will not take place in May as expected.
Preston City Council said a decision on the listing of a bus station in the city, earmarked to be knocked down as part of the plans, is the cause of the delay.
A spokeswoman for the council said: "The public inquiry into the Tithebarn retail scheme will definitely not take place in May. We are expecting a decision on the bus station to be made within the next couple of days."
Due to a decision not being made on the bus station listing by culture secretary Margaret Hodge, the council has requested a delay of around six weeks which could mean an inquiry taking place in July.
An attempt by The Twentieth Century Society to have the bus station building listed, which was constructed in 1969 and designed by Keith Ingham, could wreck the council's and developers Lend Lease's demolition plans.
The planning committee approved the Tithebarn application in July last year, but the scheme was called in by the Secretary of State, meaning a government inspector will decide on the proposals.
The scheme has long been contested by rival Lancashire local authorities Blackpool and Blackburn which say it is disproportionately large for the central Lancashire economy and will draw retail spend from their town centres to Preston.
Lead developer Grosvenor pulled out of the project last October saying it intends to concentrate on its larger portfolio of medium-sized, residential, mixed-used and retail projects instead of the few larger city centre regeneration schemes it has in its portfolio.
The proposed scheme includes 1.5m sq ft of shopping incorporating two department stores plus 100 shops. If built, there will be a range of bars and restaurants, a nine-screen cinema, new and refurbished markets, 500 homes and 2,700 car parking spaces.