Police say there are no suspicious circumstances surrounding the death of the 47-year-old, who had a long history of depression.
Ms Dawson, a former model from New Zealand, was also a high-profile victim of cyber bullying.
New Zealand Prime Minister John Key said he was “shocked” and “saddened” by her death.
Ms Dawson was best known for hosting reality TV show The Contender Australia, and for her role as a judge on Australia’s Next Top Model.
In 2012, Dawson was admitted to hospital after being targeted by cyber bullies on Twitter.
She went on to become an outspoken campaigner against internet trolls.
Ms Dawson, who left her native New Zealand at the age of 16 to pursue a modelling career, has been described by her friends as outrageous, outspoken and fragile.
‘Bright, shining girl’
In a statement posted on the Facebook page of Australia’s Next Top Model, the show’s broadcaster Foxtel said: “This is tragic news and deeply sad. Everyone at Foxtel is devastated. Our sympathies are with Charlotte’s family and friends.”
New Zealand Prime Minister Mr Key tweeted that he was “shocked and saddened” by the death.
Australian fashion designer Alex Perry also paid tribute, tweeting: “We lost a beautiful, bright, shining girl today … Rest in peace my sweetheart … I love you. X”