BOSTON (AP) — Top Democratic House lawmakers plan to write legislation to greatly expand legal rights for gay couples in Massachusetts.

The group led by House Ways and Means Committee chairman John H. Rogers, long viewed as a foe of gay rights, is considering a compromise that would outlaw gay marriage while approving Vermont-style civil unions.

The members plan to draft a bill this fall with the hope that the Legislature will act on it before the Supreme Judicial Court rules on legalizing gay marriage.

Rogers confirmed that the group will meet later this month, and said he hopes the effort will result in civil-union legislation similar to that enacted in Vermont. Lawmakers there, at the same time that they extended legal recognition to gay couples, also defined marriage as a union of one man and one woman to appease conservatives.

“My consistent philosophy throughout has been that it’s not only possible but responsible to erect new foundations of social and economic justice without tearing down a time-honored institution,” Rogers said. “We always work on extremely complex and intricate issues and somehow achieve consensus, and consensus can and has a high likelihood of being achieved this year.”

The group’s efforts mark the most serious effort yet in the House to expand gay rights. Under Speaker Thomas M. Finneran’s leadership, the chamber has blocked consideration of more modest domestic-partner benefits bills in recent years.

The House group, which has pledged to keep its deliberations secret, worked last year to strike a compromise to grant benefits to gay couples.

That attempt, which was far less ambitious that what the group of lawmakers are now considering, failed. Gay rights groups invited to meet with task force members soundly rejected the plan, and the task force stopped meeting and made a pledge never to go public.

After recent informal discussions, it is launching the effort anew. Several involved lawmakers say political ground has since shifted, with public opinion polls indicating increased support for gay marriage in this state.

Rogers, of Norwood, said he is intent on reaching an agreement this fall. He said he also believes the Legislature is the appropriate venue for the issue to be considered, rather than the courts.

He denied that he has changed his position defining marriage as being for heterosexual couples only, saying he proposed the amendment to prevent Massachusetts from being forced to recognize changes to the traditional definition of marriage passed in other states.

With polls showing Massachusetts residents favoring gay marriage, and the potential for a precedent-setting court ruling, the negotiations this year will take place against a starkly different backdrop.

Some members of Rogers’ task force may urge legalization of gay marriage.

“It’s moving so fast in the communities that people have to catch up,” said AliceWolf of Cambridge.