Mr O'Brien came under fire on Thursday over a Facebook message of support for Australian Liberal Students Federation president Xavier Boffa??? who is being investigated by police and Melbourne University authorities over his alleged behaviour.

Mr Boffa, who works for shadow attorney-general John Pesutto???, is accused of assaulting a male club member and intimidating a female colleague during an ugly stoush at the university's Parkville campus on Monday.

Mr Boffa, who says university rules prevent him from commenting, denies the allegations against him, and his supporters say the accusations are part of a factional hit-job on the club leader by his ultra-conservative enemies in the party.

After Fairfax Media reported on Thursday evening that Monday's incident had been reported to police, and that the woman was seeking an intervention order from the Magistrates Court, Mr O'Brien posted a photo on his Facebook page of himself, Mr Boffa and other young Liberals on the campaign trail.

The post drew immediate fire from high-profile young Liberal figure Stephanie Bastiaan,??? who publicly accused the shadow treasurer of supporting the "bad behaviour" of Mr Boffa.

"Why are you supporting a rogue university club president who clearly has issues with respecting women?" Ms Bastiaan wrote on her post.

"Not only has one woman had to take out an intervention order to protect herself, he failed to show respect to our female federal [vice-president] by not acknowledging her when she turned up to support the MULC [Melbourne University Liberal Club] dinner.

"I would have thought in your position as treasurer you would act to encourage a culture of respect towards women, not support ongoing bad behaviour by promoting these individuals."

Ms Bastiaan, a factional enemy of Mr Boffa, is an outspoken critic of the Victorian Liberals' leadership who failed to win preselection this year for the safe Warragul-based seat of Narracan.

The original photo, post and related comments were all removed from Mr O'Brien's Facebook page on Friday morning.

It is understood one of the young Liberal activists in the picture asked for it to be removed because they did not want to be publicly associated with Mr Boffa.

Neither Mr O'Brien nor Mr Pesutto responded to requests for comment on Friday, but their frontbench colleague David Davis distanced the party's hierarchy from the trouble on campus.

Asked if the party leadership should step in and impose discipline on the warring students, Mr Davis said such an intervention was not an option.

"They're not affiliated with the party, they're not actually part of the party, so the party arrangements don't have that option," he said.

"But I don't have the details of this matter and I'll leave that to others."

There has been concern for some time among senior Liberals within the party's organisational wing about the culture of its affiliated student clubs.

In 2014, leaked Facebook posts from Melbourne University Liberal Club members described women as "sluts", Muslims as "degenerates" and described all feminists as "ugly".