Victorian Premier Daniel Andrews' powerful letter to the Prime Minister.

In a powerful letter to the Prime Minister, Daniel Andrews has called on the government to scrap its planned plebiscite on same-sex marriage in favour of a free parliamentary vote.

Labelling it the “nation’s most expensive opinion poll”, the Victorian Premier argues conservative MPs won’t be bound by a public vote to amend the Marriage Act, regardless of its whopping $160 million price tag.

The most significant cost, he says, will be the pain that divisive politicking on the issue will cause to LGBTI+ Australians and their families, who are already widely discriminated against.

“You and I have both had the privilege of standing in front of our loved ones and committing ourselves for life to another person, and both of us were afforded full legal recognition when we did so,” he wrote in the letter, which has been published in full on his Facebook page.

Daniel Andrews and his wife Catherine on their wedding day. Source: Facebook

"At the time I did not consider it unusual that I should have the legal right to marry Catherine. I realise now how precious that right is, because I'm witnessing so many people forced to fight just to be allowed to do what I did -- marry the person they love.

"In Victoria, equality is not negotiable."

It's not the first time Andrews has written directly to the Prime Minister.

In February, he offered to resettle more than 200 asylum seekers in Victoria rather than deporting them to Nauru.

Here's some things the Government could spend the money on...