AUGUSTA — A new poll released today shows 55 percent of Mainers supporting a referendum question that would allow same-sex couples to legally marry.

The poll was commissioned by WBUR, the Boston affiliate of National Public Radio, and conducted by the independent think tank MassINC Polling Group. The survey of 506 likely Maine voters took place between June 13-14 and has a margin of error of 4.4 percentage points.

“Polling in Maine – and around the country – consistently shows that voters are changing their minds about allowing same-sex couples to receive a marriage license,” said Matt McTighe, the campaign manager for Mainers United for Marriage in a written statement. “In the past two years, we’ve had more than 88,000 one-on-one conversations with Maine voters, and we can see a difference.”

Opponents say polling on gay marriage is usually flawed. Last month, Frank Schubert, a political consultant working on the marriage issue nationwide, said polls consistently report more support for the issue because people aren’t always truthful during the surveys.

The poll question closely mirrored the referendum proposed by advocates of gay marriage and included a phrase that showed the proposed law would exempt clergy from performing same-sex marriages if it conflicted with their religious beliefs.

The draft of the Nov. ballot question released by Secretary of State Charlie Summers last week does not mention the clergy exemption, which supporters of same-sex marriage believe is significant to its passage in November.

Summers opposes same-sex marriage.

The WBUR survey’s demographics showed 53 percent of respondents were female and 47 percent male. The majority of respondents, 31 percent, were between age 45-59, while 27 percent were between age 30-44.

Thirty-four percent of respondents were independent, 33 percent were Democrats and 31 percent were Republicans.

A strong majority of Democrats favored legalizing gay marriage, while most Republican respondents opposed it.