While their sardonic elders celebrated the news that tween pop sensation Justin Bieber had jumped off Auckland Harbour Bridge, his young fans still can't get enough of him.

The 16-year-old Canadian singer has 2.2 million people following him on Twitter, and this week it seemed almost as if they were all in New Zealand.

As with Beatlemania two generations before, he was mobbed by teenage girls wherever he went in Auckland, and many took away a piece of him - a half-eaten Weetbix, an autographed chocolate wrapper, an abandoned sparkling water bottle ...

This generation's fans, though, are more commercially minded than their grandmothers: most of the memorabilia is now for sale on Trade Me.

Bids for the water bottle that Bieber drank from, before abandoning it in a TV3 makeup room, have topped $825. Proceeds will go to cancer charity CanTeen.

And a chocolate bar wrapper signed by Bieber had 21,000 views and had hit $166 by last night.

Bieber helped himself to the chocolate from a teacher's office before his private performance at Strathallan college, Karaka.

The teacher, Chris Greaney, walked in on Bieber gobbling it down and demanded he pay the $2.50 because the chocolate was being sold to raise funds for his daughter's netball team.

Bieber responded: "Oh sorry man, this is sweet chocolate but I've got no money."

The singer signed the wrapper to compensate for the five bars he and his crew had eaten.

Greaney will donate the money raised to his daughter's netball team.

He told the Herald on Sunday yesterday that he'd never heard of Bieber and was concerned at the boy's demeanour and his expectation that everything was laid on for him in life.

"I spoke to him for a while. He had this funny vibe," Greaney said. "It was quite freaky how unengaged he was. Poor kid."

C4 presenter Shannon Ryan, who has her arm in a cast as a publicity stunt to promote an upcoming show, asked Bieber to sign the cast.

The money from auctioning the piece of blue plaster, with "Nowhere but up!" scrawled on it by Bieber, will go to the Leukaemia and Blood Foundation.

Earmuffs "to dull out the drone of Bieber-fever" are also up for grabs, and include free postage. The listing has attracted a single $1 bid.