Charlotte Dawson's family say her battle against depression was just too hard as mental health advocates call for social media operators to better respond to bullying attacks on vulnerable users.
New Zealand-born Dawson, 47, was found dead in her apartment at Woolloomooloo in Sydney on Saturday after she took her own life.
The former model had suffered depression and in 2012 was hospitalised following a bombardment of vicious Twitter messages.
Dawson's sister Vicky, who lives in New Zealand, said her beautiful sister would be deeply missed.
''She was a kind, loving and generous person and worked tirelessly for the causes she believed in,'' she said.
''She fought for the underdog in many ways and won, but the most important battle, her struggle with depression, she couldn't win.''
The family of the former Australia's Next Top Model judge are expected to arrive in Sydney on Monday, with various media reporting that a memorial service is likely.
BeyondBlue CEO Kate Carnell said relentless online abuse can exacerbate mental health concerns.
'With depression, anxiety, suicidal thoughts - it's always a mixture of things,'' she said.
''I don't think we can say that it was the cyber-bullying ... but putting significant extra stress on her certainly would have made things worse.''
While Facebook has begun to actively protect users from bullying, Twitter and Instagram had some work to do to, she added.
''They've got to find better ways to be able to respond really quickly to reports of this sort of bullying,'' she said of the popular micro-blogging and image-sharing services.
After Dawson's death was announced one Twitter user wrote: ''Trolls that abused & tormented MsCharlotteD, you have blood on your hands & YOU are responsible for her death- shame on you''
The Australian government is considering reforms to protect children from online abuse including the creation of a children's e-safety commissioner, new laws to quickly remove bullying material from large social media sites and a new national cyber-bullying offence.
But Ms Carnell and former Family Court chief justice Alastair Nicholson want laws that protect everyone.
''I don't think we can stop at children,'' he said.
''There's a bit of the old concept that, 'Oh yes, we were all bullied at school, and we got over it' ...''This is a much more serious problem than we've ever accepted.''
Public submissions to the government's proposals close in March. A bill is expected to be before parliament by the end of the year.
The federal scheme for social media complaints has been criticised because it is voluntary, with no sanctions against international companies.
The Abbott government is considering a legally binding scheme with civil penalties, and has proposed a simplified cyber bullying offence that will make prosecution of trolls easier.
Bridianne O'Dea from the Black Dog Institute said Dawson's death was ''really shocking''.
Microsoft research has shown that a person's Twitter feed can predict their mental health, she said.
Dr O'Dea is conducting research to determine the impact on a suicidal or depressed person when other people respond to their tweets.
''People need to be careful how they respond to tweets and aware of how they treat people online and offline,'' she said.
Dawson's death was an example of ''a catastrophic end'', she said.
''I wouldn't say it could cause someone to take that action, but it's a contributor.''
WHERE TO FIND HELP
If you or someone you know needs to talk, these are 24-hour helplines:
Lifeline: 0800 543 354
Youthline: 0800 376 633
Samaritans: 0800 726 666
If it is an emergency call 111
For information about suicide prevention, see http://www.spinz.org.nz