The Senate today backed a motion from Greens Senator Robert Simms rejecting a plebiscite on marriage equality and calling on the Prime Minister to provide a free vote on the issue before the end of the year.

"Momentum continues to build for marriage equality in this country. Today the Australian Senate rejected a divisive and costly plebiscite and instead called on the Prime Minister to grant a free vote on marriage equality," said Senator Robert Simms, the Greens Spokesperson on Marriage Equality.

The Greens Spokesperson on Marriage Equality this morning launched a postcard campaign calling on Prime Minister Turnbull to provide a free vote on the issue in the Parliament.

"Today we have launched a postcard campaign promoting the fact that Tony Abbott and Malcolm Turnbull are still pushing the same policy position. We have had two leaders but the one policy," Greens Spokesperson on Marriage Equality, Senator Robert Simms said.

The Greens say a group of Coalition MPs who are invoking the Human Rights Charter in defence of their opposition to marriage equality are resorting to desperate measures to mask bigotry and have called on Prime Minister Turnbull to show leadership on the matter. 

"The United Nations have been running a campaign promoting equal rights for LGBTI people for years, so this is just the latest attempt by some in the Coalition to deny rights to their fellow Australians," The Greens spokesperson on Sexuality and Marriage Equality, Senator Robert Simms said.

The Australian Greens have called on the Government to stop playing tricks with marriage equality and provide a conscience vote in this term of parliament, following Prime Minister Turnbull's latest comments on a plebiscite process.

Mr Turnbull has said the plebiscite would not be a simple yes or no proposition, but instead would ask Australians to agree on a specific model.

Greens spokesperson on Marriage Equality, Senator Robert Simms, says this approach would further complicate the issue.

The Australian Greens have written to Human Rights Commissioner, Tim Wilson, calling for a review of the current 12 month blanket deferral for gay men and men who have sex with men wanting to donate blood.

Greens spokesperson for LGBTI Senator Robert Simms, said the current deferral period is discriminatory and should be scrapped:

"The Greens are concerned this blanket 12 month deferral on blood donations by gay men and men who have sex with men is discriminatory against a group of Australians," Senator Robert Simms said.

The Australian Greens have announced they will bring their Bill for marriage equality back to the Senate for debate on Thursday 12 November.

The Bill, introduced at the start of the Abbott government in 2013, would amend the Marriage Act 1961 to: define marriage as a union of two people; clarify that ministers of religion are not bound to solemnise marriage by any other law; remove the prohibition of the recognition of same sex marriages solemnised in a foreign country; and include a regulation making power so that consequential amendments can be made to other Acts.

The Greens have renewed their call for Prime Minister Malcolm Turnbull to grant a free vote on marriage equality so the Parliament can finally legislate for this reform.

"We don't need to spend over $100 million on a plebiscite to ask a question we already know the answer to. Australians overwhelmingly support marriage equality and they are looking to the Parliament to get this done. No more delays, we need an outcome," Greens spokesperson on LGBTI and Marriage Equality, Robert Simms, said.

The Australian Greens have reaffirmed their call for Malcolm Turnbull to allow the Parliament to vote on same-sex marriage.

Greens MP Adam Bandt today spoke in support of the cross-party marriage equality bill that is currently before the House of Representatives. Mr Bandt is one of the 7 cross-party sponsors of the bill moved by Liberal Member for Leichardt Warren Entsch. Mr Bandt used his speech to call on Prime Minister Malcolm Turnbull to allow the Parliament to vote on and pass this bill.