Sophie Kelly with her idol, Justin Bieber.

Sophie West with her idol, Justin Bieber.

Sophie Kelly feels like the "luckiest girl in Australia" after getting to meet her idol, Canadian singing star Justin Bieber.

But she is angry at the "mob" who ruined his live show by getting out of control early today.

The 13-year-old Sydney student had a six-day epic race across Europe to find an airport not closed by volcanic ash after she got news she was one of four teens selected to meet the 16-year-old Canadian singer.

Yesterday afternoon, her dream came true.

"We were taken upstairs into this room at Universal Studios where Xboxes were set up. Everybody was just so anxious to see Justin as more and more people were coming through the elevator," Sophie said.

"Justin came out on his skateboard and he just skateboarded for five metres and came off and said 'Hi y'all' in his Canadian accent really loudly.

"It was so cute."

Bieber was quick to thank his fans, working the room as he hugged them, took photographs and signed autographs.

"We only got half an hour with him," Sophie said.

"He played Xbox and he played this NBA game and Guitar Hero. He was really good at Guitar Hero and he was on the extreme level."

Early this morning, Sophie continued her Biebermania, joining thousands at the Overseas Passenger Terminal at Circular Quay about 5am for the singer's only Australian concert.

But as the crowd of screaming fans surged ahead in waves as they waited for Bieber to appear, girls near the front of the stage were crushed and organisers and police cancelled the show.

"Everybody was just shoving and pushing forward. They had two massive screens out and they started to play Justin Bieber songs and everybody started cheering and pushing forward more," Sophie said.

Emcee Mike Goldman, a former Big Brother host, came on stage to warn the crowd the show would be cancelled if they did not take two steps back and stop pushing.

"But he was acting like the whole thing was a joke, and he kept on adding Justin Bieber things in there and so people just kept on screaming and pushing forward more."

By the time the concert was cancelled, the fans had turned into an angry "mob", Sophie said.

"People were furious. It was a mob ... a riot was happening down there.

"Everybody waited there for another hour, screaming 'Justin Bieber, Justin Bieber' and hate messages to Sunrise because everybody was so annoyed.

"Eventually the police managed to scatter everybody and so the whole crowd moved up to Martin Place and everybody was screaming outside Sunrise wanting Justin to come."

The chaotic scenes continued outside the Channel Seven studios as Bieber tweeted to say he would perform one song there.

About 5000 girls packed into Martin Place, which turned into a mosh pit, hoping to see the star through the glass windows of the street-level studio.

Sophie said she "couldn't breathe" when she went into the mosh pit with her friends.

"There were so many people pushing you forward. And then the whole thing started to sway.

"People at either ends were falling over on top of each other. And people who fell over were trampled.

"They couldn't get up again because others were taking up their space trying to get a glimpse of Justin Bieber."

Sophie said she was over her disappointment that she had to share her half an hour with Bieber yesterday with 20 other people after this morning's mad crush.

"After today, when nobody got to see Justin, I feel like the luckiest girl in Australia."