NZME. News Service has chosen not to repeat all of Tostee's comments as the case was now before the court.
He wrote that it had been "extraordinarily difficult" to remain silent on the case.
"I have grown to believe my silence may have done more harm than good," he said.
"First off let me say that the death of Warriena was the most tragic and distressing event I have ever experienced. "Knowing I was the last person to be with her, it has left me permanently scarred and not a day passes that I don't wish I could go back in time and prevent it."
For at least a week after it happened Tostee said he was so overwhelmed, "I was unable to laugh or even crack a smile".
"I broke down in tears several times a day, or whenever I saw her picture in the news.
"I never expected I would ever experience something like this, nor did I have any idea how much it would affect me.
Even though I had only known her for a night I was horrified that this had happened to her. I would never wish for it to happen to anybody."
Tostee said he had not had a chance to speak with Ms Wright's family, but it pained him to think of the loss and suffering they must be experiencing.
He wrote that his character and image had been "destroyed beyond repair".
"Currently I am living at my parents' home, settling in. Everything has changed profoundly and I have a long road ahead of me," he said.
"I know my lawyers might crucify me for writing this but I feel that I needed to speak out as I have had no voice so far and have sustained so much abuse having my hands tied.
Ms Wright and Tostee met through the dating website Tinder while she was on holiday the Gold Coast for a wedding.
Tostee, a self confessed playboy, was known to have bragged about past sexual conquests with woman he had met online.
Before his arrest, a man reported to be Tostee boasted on an online bodybuilding forum of 150 sexual encounters, including balcony sex, but denied being responsible for Ms Wright's death.
