"Mad Monday" is a traditional day of celebration for Australian athletes in various codes at the end of the season, often involving heavy consumption of alcohol and frequently damaging the image of teams and leagues.
A photo posted on Instagram on Monday showed Dean Terlich dressed as Harris, who was sentenced to almost six years in an English jail for child abuse in July, and Alex Georgiou wearing a dress and a wig with pig-tails.
"I find it hard to believe a couple of players could turn up like that and as a footy club (we are) completely unhappy with their behaviour," Melbourne coach Paul Roos told a news conference on Tuesday.
"It's unacceptable and we unreservedly apologise to anyone that we have offended."
Roos said the club had yet to determine the exact punishment but indicated it may involve an education programme.
"I was just speechless," Roos added. "The problem with days like yesterday is they just don't think.
"There is no malice, there's no intent, there's just no thought process goes into it and I think that is the worst part about it.
"Some people take the view 'boys will be boys', I don't take that view, it's just unnacceptable."
The combination of a group of young players coming to the end of a long, hard season and alcohol has caused a string of unsavoury "Mad Monday" incidents over the years.
One of the least savoury came in 2010 when former Australia rugby league winger Joel Monaghan was sacked by his club Canberra Raiders after a photograph of the player simulating a sex act with a dog was posted on the internet.
- Sports & Recreation
- Dean Terlich
- Alex Georgiou