Malcolm Turnbull has urged Australians to ignore "extreme and unpleasant" campaign material relating to same-sex marriage.
But Labor says the Prime Minister should go further and condemn the anti-same-sex marriage posters and pamphlets, some of which are being circulated by neo-Nazis.
Posters have been put up across cities depicting a child cowering below two people brandishing rainbow belts, citing widely discredited research linking same-sex relationships to higher levels of abuse.
Australia is holding a voluntary, non-binding postal ballot on same-sex marriage from September 12 to November 7. If it shows support for changing Australia's Marriage Act, it is expected that a vote in Parliament will follow. However, MPs would not be bound to vote in line with the public.
Because the survey is being run by the Australian Bureau of Statistics it is not covered by many of the rules which normally govern election campaign material.