Fairfax MP Clive Palmer is on a hit list of federal MPs whom marriage equality advocates believe they can persuade to support same-sex marriage.
Advocacy group Australian Marriage Equality (AME) will use Valentine's Day to unveil a list of 50 lower house MPs they will target to vote in favour of a change to the federal marriage act.
The group has previously named Foreign Minister Julie Bishop, Treasurer Joe Hockey and Education Minister Christopher Pyne as high-profile Coalition MPs in their sights, while Chris Bowen, Wayne Swan and Ed Husic have been identified as Labor targets.
The hit list also includes Prime Minister Tony Abbott's parliamentary secretary Josh Frydenberg and Liberal MP Karen Andrews, who "has told her constituents she has an open mind", said AME national director Rodney Croome.
Mr Croome said many of the 50 MPs had been chosen "because they have no obvious factional or religious affiliation that would preclude them voting for reform, and because their inaugural speeches focused on principles like equality and a fair go".
Mr Croome said Mr Hockey was a target because a survey of his North Sydney electorate showed "80 per cent of young people support marriage equality".
Mr Palmer has been added to the list because he has not ruled out supporting marriage equality, while Mr Frydenberg is seen as an MP supportive of LGBTI issues and has a large LGBTI constituency in his electorate of Kooyong.
Australian Marriage Equality will use Valentine's Day to underline the continued inequality experienced by Australian same-sex couples and will launch a national "We're waiting" marriage equality campaign at Parliament House.
The push to have federal MPs support marriage reform comes after the High Court overturned the ACT's same-sex marriage laws late last year but found the federal Parliament could enact marriage equality laws.
The national campaign will call on voters to target the 50 lower house MPs in their electorates.
Based on the number of MPs who have already declared their support for same-sex marriage, Australian Marriage Equality believes it needs to persuade 25 of the MPs to vote in support of same-sex marriage.
The group expects the Liberal and National parties to debate a conscience vote on marriage reform sometime this year.
"When there is a conscience vote - and we think that is quite likely - we need every single vote to count," Mr Croome said.
"We need to be working in every single one of those electorates with grassroots supporters.''
Mr Croome said the MPs on the list were either undecided on whether to support marriage equality, or said they opposed it but the group believed they could be swayed.
He said there was strong support for marriage equality in Ms Bishop and Mr Pyne's electorates.