According to reports, the group of around 30 attempted to gather on a balcony of a Doncaster East home to take a group photo.
The railing of the large balcony remained together, but the wooden floor beneath gave way to the weight causing several to fall through and become trapped.
A 59-year-old woman died at the scene and a 37-year-old woman died in hospital on Sunday morning.
Party guest Casey Leerentveld shared her devastation at losing 'two wonderful friends and colleagues' in the tragic events.
'Just wanted to let all know I’m OK,' the Tupperware consultant wrote on Facebook on Sunday night.
'Thanks to everyone who has sent us their well wishes. Dislocated knee, fractured heel and lots of glass in my legs to be removed.
'Still in shock and absolutely devastated at losing two wonderful friends and colleagues in this tragedy.'
The partygoers were there celebrating the end of year Christmas party for Tupperware sales consultants.
Ten women and seven men, aged between 20 and 69, were taken to hospital and treated for soft tissue injuries, fractures and lacerations.
Ambulance Victoria state health commander Paul Holman said, 'This is a very tragic incident for those involved and our thoughts are with them and their loved ones at this time.'