Greens will oppose the legislation to have a same-sex marriage plebiscite, saying a national poll would harm the lives of young people. Liberal MPs, on the other hand, have warned that blocking the marriage equality plebiscite would likely delay the issue for at least three years.

Greens leader Richard Di Natale told reporters in Melbourne on Friday that the party will vote against the legislation next week. He hoped the Labor Party would join the move and block the plebiscite.

“We call on Bill Shorten in the Labor Party, indeed all of the crossbenchers, to support the Greens in coming forward in saying they will not support legislation that enables a plebiscite under any circumstances,” Di Natale said. “A plebiscite will be harmful, it’ll be divisive, it’ll be expensive, and we should never put questions of human rights to an opinion poll.

He further explained that a plebiscite would hard young people within the LGBTIQ community.

“We’ve heard loudly and clearly from people within the LGBTIQ community, from parents, from people within the health sphere, from the Australian Psychological Society -- all of whom have said to us a plebiscite has the potential to harm young people and that we will most likely see young people take their lives if this plebiscite goes ahead and the hate that will come with that is unleashed.”

Shorten has already criticised the Liberal Party’s plan to hold a plebiscite for marriage equality. On Wednesday, he said at the National Press Club that many Labor members are against it, describing the $160 million plebiscite as “ridiculous.”

“The only reason the Liberals are contemplating a plebiscite is it’s a delaying tactic,” Shorten said. “When did the rest of us sign up to spending $160 million? That is a high price to pay for one man’s job.”

The Labor, like the Greens, is concerned the discrimination LGBTIQ people would face should the plebiscite on same-sex marriage would go on. Prime Minister Malcolm Turnbull is expected to announce in September that the public plebiscite would be delayed from this year to February 2017.

Meanwhile, Liberal MPs have warned that if the legislation for plebiscite is blocked, the issue of marriage equality would also be delayed in the parliament.

Liberal MP Russell Broadbent said if the Labor party blocked the plebiscite, there would be no parliamentary vote in this term of the government. “…and they need to understand clearly that’s the proposition,” he was quoted by the Guardian as saying.

Craig Kelly, member for Hughes, agreed, saying the issue would be off the table for the next three years should the Labor kill the plebiscite.

The plebiscite will be compulsory, and those who will fail to respond will be fined. However, whatever the outcome would be, it would not be binding. The parliament may still be asked to vote again.

Read: Same-sex marriage plebiscite in Australia: Turnbull to announce delay to 2017