The Australian Greens have resolved to vote against any legislation enabling a plebiscite on marriage equality.

"No matter what the enabling legislation for a plebiscite looks like, the Greens will vote against it. We should never put questions of human rights to an opinion poll," said Greens Leader Richard Di Natale.

"The easiest, simplest, quickest, most effective, least costly and least harmful way of ensuring equality in marriage is through a vote in the parliament, and we can do that next week should the Prime Minister decide to show some leadership.

Expect more delays, says Greens Leader Richard Di Natale, unsurprised that Prime Minister Malcolm Turnbull has pushed his promised plebiscite on marriage equality off to next year

"Delays are the entire point of the Liberals' plebiscite ploy. They don't want to end discrimination in the law, they want to push it off to the never-never," Senator Di Natale said.

"The Parliament could pass marriage equality into law next Tuesday, but instead the Liberals want to run a costly and divisive public vote that may be ignored by many of their so-called representatives anyway.

The Australian Greens have today joined with crossbench senators to prevent Tony Abbott from scuttling marriage equality.

"This has been a spectacular failure of leadership from Tony Abbott," said Dr Richard Di Natale, Australian Greens Leader.

"This should have already been dealt with in the Parliament and we haven't given up hope that a cross party bill could pass.

"Tony Abbott is not proposing a plebiscite to give people a choice - he's doing it to delay and ultimately attempt to defeat marriage equality.

The Australian Greens say the MH17 disaster is a horrific tragedy that will reverberate around the world.

"Our hearts go out to the families and friends of all those who have been killed, especially the 27 Australians reported to be on board," said Greens Leader Senator Christine Milne.

"Tragedies like these always touch many more people than we can ever know, but it is shocking news that up to 108 delegates to the 20th Annual AIDS Conference due to be held in Melbourne this weekend were on board the doomed flight.