A new poll by Conservative peer Lord Ashcroft suggests equal marriage is unlikely to draw voters away from supporting a particular party.
A total of 2,060 adults were interviewed online, and 1,007 by telephone, between 31 May and 2 June for the survey.
12% said they were in favour of the government legalising equal marriage and would be more likely to vote for a party that changed the law to allow same-sex marriage.
33% said they were in favour of the idea but that the issue would not make any difference to how they would vote in an election.
23% have no opinion either way and 18% are opposed to the idea but it would not make any difference to them at the ballot box.
Only 15% would be less likely to vote for a party that changed the law to allow same-sex marriage.
A large number of Conservative Party activists believe David Cameron’s support for equal marriage is damaging their 2015 general election prospects.
On the eve of May’s local elections, which saw heavy Tory losses to the UK Independence Party (UKIP), a ComRes poll commissioned by the anti-gay Coalition for Marriage suggested equal marriage is costing the Conservatives three votes for every one gained.
When asked: “Does the Coalition Government’s plans to legalise same-sex marriage make you more or less likely to vote for each of these parties in next week’s local elections?”
Just over one quarter (26%) of Conservative 2010 voters responded by saying less likely – with only 9% saying more likely.