Governor Deval Patrick said yesterday he is studying whether he can bypass the Legislature to clear the way for illegal immigrants to pay in-state tuition at state colleges and universities, triggering criticism from Beacon Hill Republicans on an explosive issue that has reverberated nationally.

Speaking before a group of business and civic leaders, Patrick said his legal team is weighing whether the state could grant the lower rate by passing a regulation, which would require approval by the 11-member Board of Higher Education. Patrick's comments, in response to a question from an audience member, came two years after an in-state tuition bill failed in the Legislature, and amid a debate over illegal immigration in the presidential race.

Paying in-state tuition would save illegal immigrant students thousands of dollars. At the University of Massachusetts-Amherst, out-of-state tuition is close to $10,000 a year, compared with about $1,700 a year for residents. Out-of-state tuition runs as high as $8,430 a year at a community college compared to about $700 a year for residents.

California, Texas, and New York are among several states that allow illegal immigrant students to pay resident rates, but in Massachusetts a similar push failed in 2006 after an emotional debate in the Legislature.

After the breakfast, Patrick emphasized that he supports in-state tuition for illegal immigrant students but has not decided how to proceed.

"We have been asked by a number of people whether it is possible to address that question without legislation," he told reporters after the breakfast sponsored by the think tank MassINC at the Omni Parker House in downtown Boston. "The answer to that is by no means clear."

The governor's comments revived the prickly debate in Massachusetts over whether illegal immigrants should pay lower tuition. Advocates for immigrants accuse the state of punishing students - including some valedictorians - for their parents' choices and effectively shutting them out of college. Opponents of granting the lower rates say illegal immigrants should not enjoy the same benefits as residents.

The Massachusetts Republican Party issued a statement slamming Patrick for rewarding "illegal activity."

"It's bad enough to encourage and reward illegal activity while sticking it to legal immigrants and other taxpayers who obey the law, Robert Willington, executive director of the state Republican Party, said in a statement.

State Representative Bradley H. Jones, Republican of North Reading, said he would consider filing legislation to bar illegal immigrants from paying in-state tuition if the governor decided to circumvent the Legislature.

"It's the wrong policy direction to go in," he said.

In 2005, the state Senate passed a measure that would have granted in-state tuition to illegal immigrants who have lived here for at least three years, earned a high school diploma or the equivalent, and intended to seek legal permanent residency. But the measure failed in the House the next year and faced a certain veto by then-Governor Mitt Romney, who has since made illegal immigration a key issue in his presidential campaign.

But Michael Widmer, president of the Massachusetts Taxpayers Foundation, said the state could benefit by educating immigrants and integrating them into the workforce.

In 2006, his organization estimated that the state's public colleges would gain $2.5 million a year in new revenues in tuition and fees by 2009 by allowing illegal immigrant students to pay in-state rates. He estimated that illegal immigrant enrollment would grow from nearly 100 students in 2006 to 600 students in 2009, a small portion of the 160,000 public college students in the state.

"It's in the interest both economically and fiscally for the Commonwealth to allow these students to attend public colleges at [in-state] rates," Widmer said. "Economically we're losing many of these students. They are just the kind that we want to educate and who will stay in Massachusetts."

Yesterday, the governor acknowledged that granting in-state tuition to people here illegally is controversial, but he affirmed his support for it.

"I think this is the right thing to do. It's a matter of fundamental fairness," he said. "But I don't have the answer yet on how to fix this. I want to fix this, but I don't have an answer for you."