The 18-year-old Canadian flew in yesterday morning via private jet and tweeted "hate these long flights but worth it to see my fans in Australia".
However his protective minders have gagged Australian journalists from asking any hard questions.
Bieber will only undertake a handful of interviews.
Media outlets are required to send their questions to Bieber's handlers in advance.
Questions about his girlfriend, singer and actor Selena Gomez are off limits.
Gomez, who was with Bieber in Malaysia before flying to Melbourne, is expected to have followed him to Australia.
Bieber will also be shielded from questions about his alleged assault on paparazzi and using a false name after being pulled over by LA police for speeding - he said he was being pursued by photographers.
Radio hosts have also been warned off playing any jokes on Bieber, who recently hung up on an American DJ who asked him cheeky questions about his chart rivals One Direction.
Bieber, who can appear defensive and monosyllabic in interviews, will pre-record a performance on the Australia's Got Talent grand final in Melbourne tomorrow afternoon.
It will air on Channel 7 on Wednesday night.
Bieber flies to Sydney tonight and works tomorrow and Wednesday before flying out on Wednesday night.
His only official appearance will be in Sydney for Sunrise on Wednesday morning.
The star made brief appearance at the front of a Melbourne hotel to sign autographs and pose for photos yesterday afternoon.
But other fans missed out as they had gathered at the Langham Hotel in Southbank to try to see the pop idol after an unconfirmed tweet that he was staying there.
Hundreds of girls were chanting “We want Justin!” and waving up to the window of a suite at the five-star hotel.
They jumped on trains from around suburban Melbourne after Twitter rumours that the 18-year-old was returning to the same hotel that he stayed in during his visit to Melbourne last year.
Langham sources said Bieber was not staying with them this time, but his fans were undeterred saying they would wait all day.
Riana, 16, of Sandringham, rushed to the city with her friend Isabel two hours to see Bieber.
“We will wait here as long as it takes,” she said.
“We are going to tag team to get food, so if he does arrive at least one of us will have seen him.”
Isabel said she was desperate to see her idol.
“The last time he was here I was on school camp so I didn’t get to go to his concert, I cried for a whole month,” she said.
“I’m not going to let that happen again.”
news.com.au 16 July 2012
From the story: http://www.news.com.au/entertainment/music/fans-gather-at-melbourne-hotel-after-bieber-tweet/story-e6frfn09-1226426747264#ixzz20kDynp9F