Talks will begin this year between the city council and the market's new owners to look at "alternative uses'' unless ways can be found to reduce a £250,000 budget deficit.
City councillors are growing increasingly concerned that the market, which is leased by the council, in its current state will never be viable and they will be left subsidising its operation.
As part of a review of council assets and facilities the market - bought by London-based Edinburgh House Estates earlier this year as part of its multi-million pound freehold purchase of the Marketgate shopping centre - is being examined to make sure it is functioning in an "effective, efficient and economic manner.''
And officers warn that some radical changes may need to be made to stop the market continuing to drain council coffers.
Corporate director of regeneration, John Donnellon, told a cabinet meeting this week that the bottom line question was simple - is an indoor market still viable in Lancaster?
Council leader Tricia Heath said they couldn't afford to wait another two years and waste up to half a million pounds.
She said: "We do not want to see the market go but we need to find a way to make it more popular, and we shouldn't be waiting two years.
"We have a market in Morecambe that is making money and we should be doing all we can to ensure Lancaster market is the same.''
Green Coun Gina Dowding thought all the uncertainty about the market's long-term future was damaging attempts to attract new traders and said stallholders needed more security.
But Mr Donnellon added: "Most of the traders are happy with the way things are progressing and more stalls have been occupied.
"It is not the best designed building for a market and by the end of 2003 we should have spoken to the new owners and discussed various options, which could include using only part of the building as a smaller market, re-designing it to get more stalls in or using whole or part of the building for alternative retail uses.''
Chairman of the market tenants' committee, Peter Corke, said traders would be willing to listen to any ideas to improve the market. But he said Lancaster definitely needed an indoor market in some form.
He said: "It is like saying 'do we need a library?' - Lancaster needs an indoor market and with the council's help we can make this building turn a profit.
"Things have improved in the last year to 18 months and new traders have come in and even expanded and most traders are quite happy at the moment.
"But even with full occupancy, because of the way the footage was worked out on the building design when it first opened, they still wouldn't make a profit."