Labor and Liberal representatives in the Sydney seat of Kogarah where were distributed last week have strongly condemned their message.
Written in English, Chinese and Arabic, the flyer advised people not to vote for Labor "if you want to protect family value and future" or 'if you do not want your children become homosexuality".
The other side of the leaflet, which didn't include any party or group insignia, included cartoon images of a man masturbating, as well as what appears to be two men in bed and two women in bed.
The material didn't specify whether it was directed at voters ahead of the NSW election on March 23, or the federal ballot slated for later this year.
Labor member for Kogarah Chris Minns said the flyers were an "illegal and grotesque piece of material designed to mislead the community".
"I don’t think it will work and I’m disgusted that this sort of material would be distributed in letterboxes. It is pornographic in its nature and could have been exposed to young children in my electorate of Kogarah," he told SBS Mandarin.
"The people who are distributing this material are committing an illegal act because it is both defamatory and illegally distributed – it doesn’t have authorisation so it’s anonymous. I have an intelligent community who won’t fall for these smears."

Unauthorised election flyers appear in Hurstiville letterboxes. Source: Facebook
A NSW Liberal spokesperson said the party "condemns the offensive content of these flyers".
"We fully support an investigation by the NSW Electoral Commission,” the spokesperson said.
The Australian Electoral Commission confirmed that the flyer was an unauthorised piece of material.
"To be an electoral communication that requires an authorisation for the purposes of Part XXA the Commonwealth Electoral Act 1918 (Electoral Act), the communication must contain an electoral matter," a statement read.
"‘Electoral matter’ is defined in section 4AA(1) of the Electoral Act to be a ‘matter communicated or intended to be communicated for the dominant purpose of influencing the way electors vote in an election (a federal election)’."
The AEC confirmed that the Electoral Act did not specify who in a political party must authorise an electoral advertisement, sticker, fridge magnet, leaflet, flyer, pamphlet, notice, poster or how-to-vote card.

Unauthorised election flyers appear in Hurstiville letterboxes. Source: Facebook
"It is for political parties to settle who has the authority in the party to approve and issue electoral communications. The Electoral Act is concerned that authorisation on an electoral communication helps voters to understand who is making the communication or on whose behalf the communication is being made."
SBS Mandarin has requested comment from the NSW Electoral Commission.