Pressure is mounting on the West Australian Liberal Party's candidate for the marginal state seat of Midland, after he attracted more controversy over his comments on social media.

Deputy Premier Liza Harvey said Daniel Parasiliti may need to reconsider his position as a candidate, after it emerged he referred to a woman in a television commercial as a "d-class celebrity with a head like a 1/2 eaten pie".

The comment was made on Twitter in 2013, after Mr Parasiliti had already contested the seat of Midland at that year's election.

The 33-year-old physiotherapist has been preselected to recontest the seat at the 2017 election, but there were calls for him to be dumped following the emergence of offensive comments he posted on Facebook eight years ago.

Mr Parasiliti said he had learned from those mistakes and apologised for those remarks, which included a graphic sexual comment he made to a woman that emerged last month.

Mr Parasiliti's Twitter account appears to have been recently deleted.

Mr Parasiliti appears to have deleted his Twitter account since the emergence of the comment, about a woman in a skincare commercial.

Mrs Harvey, who is also the Minister for Women's Interests, said she was unaware of Mr Parasiliti's Twitter comment before she was questioned about it but admitted it was "not terribly professional".

"Once you put it out on social media it is there forever, in that context if there is more of these matters with Daniel Parasiliti, he may need to reconsider his position," she said.

"But I don't know what was involved, I don't understand any of the context that it was in, so I am not really willing to condemn someone and say they should throw away their career without understanding the context."

Premier Colin Barnett gave Mr Parasiliti his backing after the previous controversy over the candidate's social media comments, saying he was a young man at the time who had learned from his mistakes.

Mr Parasiliti fell just 24 votes short of unseating long-serving Labor MP Michelle Roberts in 2013.

Labor renewed its call for the Liberals to dump Mr Parasiliti as their candidate, saying it was another example of him making unacceptable comments.

"He has shown a pattern of behaviour over the last eight or so years, all as an adult," state Labor MP Simone McGurk said.

"The Liberal Party should have standards and if Mr Parasiliti won't stand down then the Premier should step in."

Ms McGurk would not be drawn on any comparison between Mr Parasiliti and Labor Senate candidate Mark Reed, who attracted controversy when it emerged he compared Gina Rinehart to Star Wars character Jabba the Hutt in a 2012 Twitter post.

The Liberal Party has been contacted for comment.