BOSTON (AP) – A lobbying group that supports same-sex marriage has started making campaign contributions to candidates in tight races for state office in an effort to tip the legislative balance against a proposed amendment to the state constitution banning same-sex marriage.

The Freedom to Marry Political Action Committee, formed earlier this year, has already raised nearly $15,000 and spent nearly $6,000, the bulk of it in $500 contributions to 10 legislative candidates, according to campaign finance records.

Sept. 7 was the filing deadline for candidates and political actions committees ahead of the primary election.

The goal is to help backers of same-sex marriage put their money where their mouths are by giving them another vehicle to support candidates sympathetic to their cause, group spokesperson Josh Friedes said.

“The gay and lesbian civil rights community is very serious about supporting candidates. They know it’s not enough just to call their lawmakers,” he said.

A group formed to support candidates who oppose same-sex marriage, The Heritage Alliance Political Action Committee, has not been able to raise a significant amount of money and has not made any contributions.

Michael Carl, who formed the group, has decided that instead of raising money he will concentrate his efforts on volunteering time for the campaigns of candidates who oppose same-sex marriage.

“I’ve signed on with several campaigns,” he said. “I’d rather go out and press the flesh and talk up the candidates I’m personally supporting, those who support mainstream values.”

Friedes said the contributions are not necessarily timed for the primaries, but are also designed to help candidates preparing for November’s general election.

“We’re clearly putting our money into races that we think are important – races that are contested, typically where there is a significant challenger who opposes gay rights,” he said.

One of those races is a rematch of a special election earlier this year that pitted Democrat Angus McQuilken and Republican Scott Brown for the state Senate seat held by McQuilken’s former boss, Cheryl Jacques. Jacques resigned her seat to head the Human Rights Campaign, a national gay-rights organization.

Brown, who won a narrow victory, voted in favor of the proposed amendment defining marriage as between a man and a woman, but establishing civil unions for same-sex couples. McQuilken opposes the amendment, saying same-sex couples should have full marriage rights.

Friedes’ group made a $500 contribution to McQuilken, the maximum allowed under state campaign finance laws.

The group also gave $500 to state Sen. Pam Resor, a Democrat from Acton, who supports same-sex marriage and opposed the proposed amendment. Resor is among a handful of Democrat incumbents Republicans believe they have a chance of ousting in November.

A joint session of the House and Senate voted 105-92 in favor of the proposed ballot question in March. The amendment must be approved a second time during the next legislative session, which begins in January. The soonest it could go before voters is 2006.