Oliver, who is well-known for adding his satirical spin on complex social and political issues, labelled the survey "toxic" and the "weirdest waste" of taxpayers' money.
He took aim at the money being spent on the Turnbull government campaign.
"It is an odd thing to do because polls already exist showing around two-thirds of Australians support it [marriage equality] so parliament could simply pass it into law," Oliver said.
"But instead they are inexplicably holding a non-legally binding voluntary postal vote at a public cost of $120 million, which is the weirdest waste of Australian money since every Baz Luhrmann movie."
The comedian turned his attention to 'No' campaigners as he laughed off the term "garriage", which was raised in 2016 by lobbyist Sophie York from Marriage Alliance.
"Garriage, that is a stupid word. Except in the very rare case of a wedding between two men named Gary, in which case obviously they should be getting 'garried'," Oliver said.
After turning his attention to a report from ABC's 7.30 that showed a gay couple who said they would not walk down the aisle if same-sex marriage was legalised, he raised the issue of violence during the postal survey.
Former Australian prime minister Tony Abbott addresses the media outside the Henry Jones Art Hotel, Hobart, Tasmania, Friday, September 22, 2017. Source: AAP
Oliver said the campaign had been "toxic" bringing up the moment Qantas CEO Alan Joyce was struck in the face with a pie and when former prime minister Tony Abbott was allegedly headbutted in Tasmania.
"It's true, Tony Abbott was [allegedly] headbutted by this man, a Tasmanian... who goes by the name Astro Labe and even better, DJ Funknukl," he said.
"But it turns out according to DJ Funknukl the [alleged] attack wasn't connected with the gay marriage issue at all.
"So the point is this has been a dispiriting and ultimately pointless process and at the end of the day I think only two good things that could come out of it.
"One is the Australia parliament legalises gay marriage at the earliest opportunity."
