A CHRISTIAN lobby group fears the Federal Government could join the Queensland Labor Party and back same-sex marriage.

The state conference of the ALP's Queensland branch yesterday passed a motion calling on both federal Labor and the ALP national conference to support same-sex marriage.

The Australian Christian Lobby (ACL) is worried federal Labor could follow Queensland's lead when it meets for its national conference in December.

"We have appreciated Prime Minister (Julia) Gillard's resolve to honour Labor's commitment but we are worried about elements of the party who are seemingly dismissive of the party's election promise and are following the Greens' lead on redefining marriage," the lobby group's chief of staff Lyle Shelton said.

"ACL urges delegates to the federal conference in December not to break Australia's bi-partisan support for marriage being between one man and one woman."

Ms Gillard last week reaffirmed in Parliament the Labor Party's commitment not to support gay marriage.

Federal Labor MP Shayne Nuemann, who represents the Queensland electorate of Blair, today backed Ms Gillard's comments, saying he did not support same-sex marriage.

"But that's a matter for national conference (and) federal caucus at some stage in the future and I'll have my say there," he said.

Mr Shelton said the changing of federal laws in 2008 to give gay couples the same rights as de-facto heterosexual couples meant issues of equality had been dealt with under the law.

"But equality under the law does not mean that marriage should be redefined," he said.

"This debate would be understandable if there were issues of substantial inequality but there are none."

Mr Shelton said the Queensland Labor Party risked alienating mainstream voters by fixating on a small, activist component of the population instead of dealing with the issues most Australians were concerned about.

Originally published as Christians fear government on gay unions