Taking aim at price-gouging gas stations, the City Council is expected to pass a bill this week that would ban fuel sellers from changing prices at the pump more than once a day.

The proposal has met with opposition from the gas industry and the Bloomberg administration. The bill would require that a gas retailer maintain a posted price for at least 24 hours or face stiff fines.

While council members say the bill is necessary to curb incidents of price gouging, critics argue that it impinges on the free market and could even exacerbate the gas crisis.

“The free market system, left alone, not only allows but encourages price gouging,” a lead sponsor of the bill, Council Member John Liu of Queens, said.

A similar bill was introduced in the council last year after Hurricane Katrina, when consumers saw prices at the pump rise two or three times a day. Industry officials say stations rarely hike rates more than once a day, and that in the case of Katrina, retailers were forced to raise prices to keep up with rising wholesale gas costs.

An artificial cap on price increases could lead to further destabilization in the fuel market, because retailers who could not respond to wholesale increases would be forced to sell gas at a loss and would be unable to afford the next day’s shipment, the president of the New York Association of Convenience Stores, James Calvin, said. Those stations could end up shutting down.

“The retailer may decide that I can’t afford to give away gas. I can’t afford to sell gas at a loss,” Mr. Calvin said.

Mr. Liu said the bill was targeted at retailers that increased prices without a corresponding rise in the supply cost, but neither he nor Mr. Calvin said they were aware of specific instances of that occurring.

The city’s Department of Consumer Affairs testified that the bill would impose an undue burden on the market, but aides to Mayor Bloomberg would not comment on whether he would veto the measure.