In what would be a rare break in its recent relations with the mayor, the City Council today is set to override his veto of a bill barring gas stations in New York City from hiking their prices more than once a day.

Mayor Bloomberg has dismissed the bill as anti-business.

The mayor’s relationship with the council has been marked by an unusual degree of comity since Christine Quinn ascended to the speaker’s chair, but the era of good feeling will face a test as the council for the first time is poised to overturn a veto of legislation introduced during her tenure.

If the veto is overturned, gas stations citywide starting sometime in October will need to keep a log to help city auditors inspect to make sure prices are not hiked more than once in 24 hours.

In a July letter explaining his veto decision, the mayor said the bill would ultimately hurt consumers by interfering with businesses and increasing their costs due to “unnecessary paperwork.”

“Telling a business how often it can change its prices is just not something that the city should do,” Mr. Bloomberg wrote. “It does not address the real issue, and unduly interferes with private enterprise.”

A council member who sponsored the bill, John Liu of Queens, said laissez-faire markets must be checked because they will not sufficiently control fuel price gouging.

“Every consumer protection measure defends consumers against a free market that takes advantage of situations,” Mr. Liu said.

The mayor said in his July veto statement that existing city rules adequately guard against fuel price gauging.

The gas bill is not just bad for businesses, an industry group said, but it could ultimately hurt consumers by encouraging panic buying during crises like Hurricane Katrina, when costs rise on the retailer’s end.

“The bill, to us, is pointless,” the president of the New York Association of Convenience Stores, James Calvin, said yesterday. “To tell businesses at the retail level that they can’t respond to changes in wholesale prices that are beyond their control seems to me to be silly.”

Mr. Calvin surmised that legislators are responding to political pressure from constituents angry at high prices at the pump.

“The council needs to do what they need to do in order to create the illusion that they’re doing something about gas prices,” he said.

Despite the disagreement between the mayor and the council about regulating fuel prices, some council members are promising to continue cooperating with the mayor.

“In every relationship, there are disagreements,” Council Member Leroy Comrie said. “This is something that we’ve agreed to disagree on.”

The council overturned a mayoral veto once before under Ms. Quinn, but the vetoed legislation — of a so-called Wal-Mart bill forcing large grocery stores to subsidize health benefits — was introduced before Ms. Quinn became speaker.

Also today, the council will consider a proposal to rezone part of North TriBeCa, a plan that would affect the area’s residential density.