Tween star Justin Bieber urges fans to calm down

Fans ask for an autograph from singer Justin Bieber on the red carpet of the Juno Awards outside the Mile One stadium in St. John's, Newfoundland April 18, 2010.

SYDNEY (Reuters) - Tween pop idol Justin Bieber appealed to his fans on Wednesday to calm down after his hat was stolen and his mother knocked over by a crowd of about 500 waiting to greet him as he arrived in New Zealand.

The frenzy came after Australian police on Monday canceled a live performance in Sydney by the 16-year-old Canadian singer when a crowd of about 5,000 teenage girls got out of hand, with about eight youngsters injured in the crush and others fainting.

The hysteria surrounding Bieber, who is traveling to promote his debut album "My World 2.0," has sparked comparisons to the reaction of young fans when The Beatles went on tour in the 1960s.

"Finally got to New Zealand last night," Bieber told his 2 million-plus followers on the micro-blogging site Twitter.

"The airport was crazy. Not happy that someone stole my hat and knocked down my mama. Come on people... I want to be able to sign and take pics and meet my fans but if you are all pushing security won't let me."

Bieber shot to fame after being discovered on YouTube where his mother had posted videos of him singing at talent shows. He was signed up by rapper Usher's record label Island Def Jams Music Group at the age of 14.

His album "My World 2.0" hit the No. 1 spot on the Billboard charts in the United States within a week of its release last month.

(Writing by Belinda Goldsmith, Editing by Miral Fahmy)