If a group of state legislators have their way, local alcohol consumers soon may have an extra day to purchase their libations.

By a vote of eight to seven, a bill that would allow Mass. liquor stores to sell alcohol on Sundays squeaked through the joint Government Regulations Committee earlier this week, clearing the way for its consideration by the full House of Representatives in the near future.

But even if the legislature were to approve the switch to weeklong sales, local merchants and Cambridge License Commission official said the change would at best garner lackluster support from city retailers and would face considerable opposition from community groups.

As it is written, the bill would grant cities and towns the power to allow liquor stores within their borders to open for business on Sundays--a practice currently forbidden by state law except in communities that are within 10 miles of the Vermont and New Hampshire state lines.

A Superior Court decision in August invalidated the restriction, ruling that the law was arbitrary because it did not allow all state stores the opportunity to stay open.

The Cambridge License Commission would be responsible for ultimately making that decision in the City of Cambridge, according to Richard V. Scali, the group's executive officer.

But Scali said the shrinking number of stores licensed to sell alcohol in the city and the relative lack of large local competitors mean that proportionally fewer Cambridge stores may have interest in staying open for the extra day--traditionally considered one of the slowest sales days of the week.

Scali said that when the state legislature repealed a similar regulation--known as the "cordials law"--about five years ago, only a handful of local businesses expressed an interest in gaining the right to serve alcoholic beverages before noon on Sunday. That lack of interest encouraged the Commission not to repeal the restriction.

And for small retailers who would be required to pay employees time-and-a-half rates for hours worked on Sunday, the opportunity to extend their hours may offer slim economic advantages.

State law currently permits liquor stores to stay open on the six Sundays between Thanksgiving and New Year's Day. But even then, Scali said, the extra business has not been spectacular.

"The evidence we have seen...is that they're not really busy on the Sundays during the holidays," Scali said.

And retailers said pressures to stay open all Sundays simply to mimic other shops may not be cost-effective.

"Most small businesses now have trouble with staffing as it is," said a manager of a local liquor store who asked to remain anonymous. "I'm not sure it would be worth our while to stay open, but if everyone else was, we'd probably have to be."

According to Jeffrey A. Kaplan, manager of University Wines on Mass. Ave. near Porter Square, the new law would be more significant for retailers in the vicinity of the state line who face competition from New Hampshire and Vermont liquor stores that are permitted to stay open on Sundays.

"The drive up to New Hampshire for alcohol has been a legend for some time," Kaplan said. "This isn't groundbreaking [for us]."

Still, Scali said he thought Cambridge's "active neighborhood groups" would likely be against any effort to expand the sale of alcohol.

"I'm sure they'll come out and fight it if it gets proposed," he said.

He said, however, that the high concentration of college students in Cambridge would not seriously affect any effort to get the change passed in the city.

"People from Harvard and MIT don't really drink or buy their alcohol in Cambridge," he said, referring to results from recent sting operations designed to nab underage drinkers. "I guess you don't buy in your own backyard."