A Government MP who has long campaigned within the Coalition for same-sex marriage has accused Opposition Leader Bill Shorten of playing politics with the issue.

Key points: Warren Entsch disappointed Labor will not back plebiscite

Warren Entsch disappointed Labor will not back plebiscite Nick Xenophon Team senators to decide their position on issue this week

Nick Xenophon Team senators to decide their position on issue this week Pauline Hanson concerned over cost of national vote

Over the weekend, Mr Shorten indicated Labor was prepared to block enabling legislation to hold a plebiscite, although he stopped short of saying Labor would do that before the party sees legislation.

The announcement came after the Greens confirmed they would vote against the legislation.

North Queensland Liberal National MP Warren Entsch said he does not want a vote of MPs to change the definition of marriage, instead calling on Labor to back the plebiscite.

Mr Entsch told the ABC it was "profoundly disappointing" that Labor did not accept the Coalition's policy, given it was taken to an election they won.

He added that Prime Minister Malcolm Turnbull did not have the option of holding a vote in Parliament.

"As soon as we do that, your mob in the media and of course the Labor Party will be all over him, attacking him for doing a backflip," he said.

"If this is lost, if this sort of nonsense continues, there's a high probability that this will be argued over the next three years of government and it will come up again to the next election.

"This is a commitment he made. Give him a chance to deliver on it."

The Coalition needs the support of an additional nine senators to pass the legislation.

The three Nick Xenophon Team (NXT) senators and Derryn Hinch have cast doubt over the plebiscite, and if they vote against it, it means the Government needs Labor's support.

Mr Entsch said Parliament needed to pass the legislation and move on with the issue.

"I've committed a lot of years, getting to the point where we are now. I've copped a lot of flak from within my own party and from outside," he said.

"I've got other issues that I have to deal with ... and I'm not going to sit here and fiddle around year after year because someone doesn't get exactly what they want."

Mr Entsch last year introduced a private members bill to legalise same-sex marriage, co-sponsored by Labor's Terri Butler.

Labor Senator Penny Wong labelled the plebiscite a "political deceit".

Senator Wong told the ABC that Labor still had "deep concerns" over the plebiscite, saying pressure needed to be applied to the Coalition over the issue.

"The plebiscite is a political deceit imposed upon the Coalition by Tony Abbott and the conservatives," she said.

"It would be expensive, divisive and it is non binding... It is a deceit that Malcolm Turnbull doesn't agree with. We know that because before he became Prime Minister, he argued against it."

Senator Wong cited concerns over the potential for hate speech.

Deputy Labor leader Tanya Plibersek brushed off concerns about potential delays on the issue if the legislation to enable a plebiscite was not passed.

"If there is any delay to the legalisation of marriage equality, it will be on Malcolm Turnbull's head," Ms Plibersek said.

"We could legislate for marriage equality by the end of this week. There could be legislation on Wednesday, if Malcolm Turnbull allowed it."

Xenophon team weighs plebiscite stance

If Labor decides to block the legislation to set up the plebiscite, its fate will rest with the three Senate votes of the NXT.

Senator Xenophon told the ABC they would decide this week how to vote as a block.

"I cannot see the point of the plebiscite," he said.

"Why would we spend $160 million on what, in effect, would be the world's most expensive opinion poll?

"It won't be binding. It is something the Parliament itself should be deciding on."

The South Australian senator said he was scheduled to meet with advocates for the plebiscite this week.

"I know what my other colleagues have said publicly and privately in relation to this, but in terms of due process, we will tell people where we stand," he said.

He also called on the Opposition to make its position clear.

"It seems to me that the ALP needs to make up their mind on this as well, so Australians know where the Parliament stands on this issue once and for all," Senator Xenophon said.

'Put the vote to the people': Hanson

Crossbench senator Pauline Hanson, whose party holds four crossbench positions, said she wanted the vote to go to the public at the next election.

Senator Hanson told Channel Seven she had concerns over the cost to the taxpayer.

"I would like to see it go to the next election and be put to the people," she said.

"Put the vote to the people at the time, because of the cost involved in all of this."

Senator Hinch also cited concerns over costs, but instead wants a vote in Parliament.

"The politicians should do it," he told Channel Seven.