The Liberal candidate who linked same-sex marriage to paedophilia will soon be on the gay dating app Grindr — in a Labor Party advertisement highlighting his contentious views.

Key points: Gurpal Singh was a 'No' campaigner ahead of the 2017 same-sex marriage plebiscite

Gurpal Singh was a 'No' campaigner ahead of the 2017 same-sex marriage plebiscite Liberal politicians have defended Mr Singh, saying he apologised for his comments linking same-sex marriage to paedophilia

Liberal politicians have defended Mr Singh, saying he apologised for his comments linking same-sex marriage to paedophilia The Labor Party will run negative ads about Mr Singh's comments on Grindr and Instagram

The advertisement, to run on Grindr and Instagram, features a photo of Scullin candidate Gurpal Singh and part of a newspaper article reporting on his remarks.

He made the comments in an interview with SBS Radio in 2017, in which he also suggested children raised by gay and lesbian parents were at risk of sexual abuse ahead of the nationwide plebiscite.

"I think it is also an issue of paedophilia," Mr Singh told SBS Radio.

"In these situations the occurrence can be high."

The ALP's social media campaign featuring Mr Singh will launch tomorrow, using location and other data to target voters in the inner-Melbourne seats of Macnamara, Higgins and Kooyong.

The 'Yes' vote in those electorates was 82 per cent, 78 per cent and 74 per cent respectively.

Labor will also release Facebook ads attacking another Victorian Liberal, candidate for Chisholm Gladys Liu, who the ALP has accused of expressing anti-gay sentiments.

The Greens used Grindr in the 2016 election to promote Lower House candidates in Melbourne.

Prime Minister Scott Morrison yesterday said Mr Singh's preselection was secure.

A week earlier he warned "the standard you walk by is the standard you accept" in relation to controversial candidates.

Victorian Liberals have publicly defended the candidate for Scullin since his candidacy was confirmed.

Treasurer Josh Frydenberg said Mr Singh was a strong 'No' campaigner ahead of the vote that led to the Parliament legislating same-sex marriage.

"He did say them [the comments] in 2017 and he was a vocal opponent of same-sex marriage," Mr Frydenberg said.

"We don't accept those comments and again, as I said, he has apologised."

Mr Frydenberg on Sunday said: "We don't want people with extremist views in our party."

Mr Singh, a Sikh, was born in Punjab, India.

"He comes from a background where those sorts of views are more widely held with regards to the marriage equality debate," Katie Allen, the Liberal candidate for the Melbourne seat of Higgins, said.

"When I was handing out for marriage equality, the people in Higgins who were less likely to support it often came from an Indian background because in that culture it's a very different situation."

Ms Allen said the comments were "completely unacceptable" but said she was concerned the Liberal Party was viewed as "homophobic, anti-women, climate change deniers".

The outgoing member for the inner-Melbourne electorate Kelly O'Dwyer reportedly described the party in those terms following its Victorian election defeat.

Scullin is a safe Labor electorate in Melbourne's north held by Andrew Giles. It is a seat that only narrowly voted in favour of same-sex marriage.

"Not only have the PM and Mr Frydenberg not taken action regarding his [Mr Singh's] candidacy, they haven't even said sorry to LGBTI Australians. Standards," Mr Giles said.

The Liberal Party last week dropped one candidate over homophobic comments and two candidates over anti-Islamic remarks.

The ALP disendorsed Senate candidate Wayne Kurnorth over online posts which included a conspiracy suggesting the world was being run by a society of Jewish shapeshifting lizards.

Another Labor candidate, Luke Creasey, withdrew after social media posts came to light which showed him engaging in inappropriate jokes about rape, lesbians and Catholics.

The Greens dropped their candidate for the Melbourne seat of Lalor yesterday over distasteful posts on Facebook, in which he joked about having sex with dead people and made a racist joke about an Asian friend.