Tensions have emerged within the Victorian Liberals after an adviser to Opposition Leader John Pesutto was preselected for a by-election triggered by the resignation of Daniel Andrews.
The Victorian Liberals on Wednesday preselected Courtney Mann for the November 18 poll to replace former premier Daniel Andrews as Mulgrave MP.
Mr Mann ran as the Liberal candidate for Mulgrave at the 2010 state election and is a senior policy adviser in Mr Pesutto's office.
He also has previous experience as an adviser in the Baillieu/Napthine Victorian coalition governments.
Mr Pesutto said Mr Mann had deep roots in the electorate, having grown up in Mulgrave and lived there for 25 years.
"He is highly respected across the party and, if elected, would provide a strong voice for the people of Mulgrave in the Victorian parliament," he said in a statement.
Following the preselection, Michael Piastrino, the Liberals' candidate for Mulgrave in last year's state election, took to social media to express his disappointment in the result.
"What's happened to the Liberal Party?" Mr Piastrino said in the Instagram story.
"You guys want puppets who are gonna go, 'yes, yes, yes'.
"You guys have just missed out on a great opportunity to make the Liberals great once again."
Mr Mann prevailed over other candidates Jeff Kidney, Anthony Scarcella and Liz Walker.
The former candidate had supported Mr Scarcella in the preselection battle.
"We will not support the Liberals," Mr Piastrino said following the preselection result.
"My contacts, Anthony's contacts, no one, we will be supporting Ian Cook all the way."
Mr Piastrino's now-preferred candidate, Ian Cook, is suing the Victorian health department after he was ordered to shut his catering business over the listeriosis-linked death of an elderly woman.
Mr Cook confirmed he would recontest the seat as an independent after collecting the second most first-preference votes last year.
Mr Piastrino posted a photo of himself with Mr Cook on his Instagram story with a caption tagging the independent candidate and words reading, "support the man".
Labor holds the seat on a 10.2 per cent two-party-preferred margin, but it could be reduced following the retirement of Mr Andrews last month after more than 20 years as the local member.
Dandenong mayor Eden Foster, who grew up within Mulgrave's suburbs of Noble Park and Springvale, has been locked in as Labor's pick to succeed him.
Ms Foster's fellow councillor Rhonda Garad was preselected as the Victorian Greens' candidate.
Nominations for the Mulgrave by-election close next week.
