The family of a teenager who took her own life after being harassed over the internet has sent a message about the dangers of cyber bullying.

Sheniz Erkan took her own life on Monday, just a week before her 15th birthday, after being victimised by online bullies.

It was a secret she kept hidden from her family and friends for 'a long time' and one that eventually led to her tragic and untimely death.

Sheniz's brother Aykut Erkan says his sister was bullied and tormented on social networking sites.

Bullying victim: Sheniz in happier times. Photo: Facebook

Aykut has taken aim at his sister's tormentors, saying their relentless harassment forced his little sister to 'crack'.

"Cyber bullying has become the new playground," he told 7News.

"You come home and it doesn't leave you, it keeps going and going.

"A person must feel so much pressure."

Sheniz's sudden death has left her devastated family wondering why she never spoke up about her troubles.

They warn the tell-tale signs of bullying are not always evident for parents to see.

"We never thought this would happen," Aykut said. "She was always so bubbly and energetic - everyone knew her like that, even her soccer team mates at school, friends.

"Obviously there was a side she was keeping from us, the side that no one knew about."

Sheniz's father Senol Ekran said his daughter was always trying to help others, but couldn't help herself.

"She never showed us anything to make us think there was something wrong," he told 7News.

"She showed no sign of anything, she kept it inside and tried to be as normal to us and happy.

"She was burning inside and we didn't notice."

Close friends say even they were not prepared for what was to come.

One friend said: "At school she was like the bubbly one, she was the class clown, at school I doubt she got bullied, but outside school...who knows."

Find out more about national youth organisation, Headspace

Sheniz's family say someone had been hacking into her Facebook, and sending messages using her profile.

Now they are calling on others to take a stand against bullying, and report incidents of harassment before another innocent life is lost.

"It's too late for our daughter," Mr Erkan said. "But we want to send a message to others. Kids, if you know anything about your friends, tell somebody - tell, ring and say.

"I don't want any other parent to feel the pain that we're going through now. I don't want any person to lose their loved one. Please do something about it."

Thousands expected at Sheniz Erkan's funeral. Photo: Facebook

A Facebook tribute page set up for the Taylors Lakes pupil has more than 16,000 followers, and Sheniz's family expect thousands to attend her funeral tomorrow.

Hundreds of mourners have also left tributes at a memorial site in Sydenham.

But even after death, Sheniz's tormentors refuse to relent.

The tribute page has already been marred by mindless bullies leaving hurtful comments.

Taylors Lakes' principal Geoff Pell said in a statement that all students did take part in a cyber bullying program last year and a team of counsellors is being put together.

Sheniz's family say they want justice for the teen, and the perpetrators punished.

"I don't think they take into account or have any fear of the repercussions and what's going to happen to them," Aykut said.

"It's easy to get onto a keyboard or hide behind the computer screen and write whatever you want without consequences."