A protective services officer who gained a woman's personal details at a train station later wrote to her on Facebook, saying she had "amazingly beautiful eyes", a report on misconduct has revealed.
The report by the Independent Broad-based Anti-Corruption Commission found the officer had acquired the woman's information after she was caught smoking on a train platform.
The woman later received a post from the officer on Facebook about restrictions on smoking. He assured her she wouldn't be fined, before commenting on her eyes.
The incident was investigated and the officer "received workplace guidance".
However, the Police Association slammed the report as an "unfair representation" that undermined the good work and standing of PSOs in the community.
The report examined the conduct of PSOs on public transport. It said complaints about predatory behaviour "most commonly" related to PSOs targeting young women to obtain personal details so they could contact them socially.
"A PSO may have a lawful reason for approaching and requesting a person's details; however, it is not lawful to request personal information to pursue a relationship," the report said.
Predatory behaviour accounted for 17 per cent of all allegations against PSOs. However, the report said predatory behaviour involving "vulnerable community members" was likely to be under-reported.
A separate police investigation found that PSOs were not over-represented in investigations into predatory behaviour and sexual assault.
The Police Association said the report failed to exclude "allegations investigated and found to be unsubstantiated".
"This provides a critical misrepresentation of scale and reality of complaints received that relate to PSOs," it said.
The association argued the report also failed to account for the huge rise in transit PSOs from 88 officers in 2012 to 940 in June 2015.
"It follows that the number of public contacts, arrests and interactions that these officers will have with offenders and others in the community will increase similarly."
The association's Secretary, Ron Iddles, said: "Our members when they work on the public transport system late at night are often confronted with people drug and substance affected, often violent and unco-operative."
The IBAC report found most excessive force allegations were at the "lower end of the scale in terms of seriousness".
It reviewed complaints and "use of force" data from February 2012 until the end of 2015.
It recommended that Victoria Police consider reviewing training provided to PSOs, including professional and ethical standards.
The report said police had already developed and introduced programs to address the recommendation.
The provision of protective services officers on train stations was a commitment by the previous state government.
The officers patrol railway stations in the evenings until the last service.