Bieber makes time for mum on trip

Promotional duties may be the priority for Justin Bieber on his Australian visit, but the star still made time in a radio interview to take a call from his mum.

Bieber begun the first day of a packed media program in Sydney on Tuesday by fielding carefully vetted questions from Kyle & Jackie O on their 2Day FM morning show.

Interviewers on his trip have been warned against quizzing the 18-year-old about his romance with Selena Gomez or his run-in with a paparazzi snapper.

But unlike a recent interview in the US, when Bieber hung up on the presenter over a joke about his mother, the subject was not off limits.

Following an on-air phone call in which a bemused Pattie Mallette told her son she missed him, Bieber gushed about his "young mom" who had him at 18.

"She's amazing - I was definitely an accident, it's great my mom is super young," he said.

"She's a friend and a mom, she's always been really strict, she still keeps me in line."

Bieber fever has dominated social media sites since the singer landed in Melbourne on Sunday as part of a three-day trip to spruik his album Believe.

With an arena tour likely to be announced soon, Bieber said he preferred travelling to play concerts than talking up his latest release.

"I like the actual tour, the promo tour is all the photoshoots, interviews all the stuff that I don't really like," he said.

Following a string of interviews, Bieber will perform acoustic tracks at a secret Channel [V] show on Tuesday afternoon and three songs on Sunrise on Wednesday morning.

He recorded two songs on Monday for an episode of Australia's Got Talent in Melbourne, when he was mobbed by fans travelling to and from his hotel.

Bieber was also hugged onstage by a 14-year-old fan while the singer was giving a post-performance interview to the TV talent show's host Grant Denyer, according to news.com.au.

Bieber is clearly loving the attention, writing on Twitter: "LOVING AUSTRALIA!"