A young woman who slid to her death in a wheelie-bin down the world's steepest street has been described by her best friend as an angel with a zest for life.

Ana Louise North, a 19-year-old physical education student at Otago University, died instantly when she and a friend smashed into a parked trailer while riding in a green wheelie-bin on Dunedin's Baldwin St yesterday.

The 2.30 am prank left her male friend, Lindsay Peter Roxburgh, originally from Pukekohe, in Dunedin Hospital with serious head injuries.

The pair took the wheelie-bin from another part of town to Baldwin St, pushed it up the road and laid it on its side, before getting in and riding it like a sledge.

Baldwin St is the steepest public street in the world, with a 38-degree gradient. It is in the Guinness Book of Records, and is a tourist attraction.

The tragedy has devastated Ana's family and dampened Otago's two-week student orientation festival, which ends today.

Ana North's lifelong friend Natalie Hassan, who was with her for most of Wednesday night, told the Herald: "I'm still really shocked. It really hasn't sunk in yet ... but it's so going to hit me because I really depended on her."

Ana was a kind, gentle person. "She's been my friend for life. She was fun-loving. She'd walk into a room and everyone would become her friend.

"She had the best attitude. She reminded me of an angel."

Ana had always been into having fun but "that's probably the craziest thing she's done."

One of Ana's aunts, Vicky Frater, told the Herald: "We're just a bit shattered at the moment ... devastated with the loss of someone so incredibly special."

Ana was born in Blenheim and lived with parents Bruce and Sharon and younger teenage sister Emily.

She attended Marlborough Girls' High before moving last year to Dunedin, where Natalie Hassan was studying.

She took psychology and some other courses, but this year decided to study physical education. Her aim was to either join the Army or become a police officer.

On Wednesday night, Ana and Natalie Hassan decided not to go to the New Zealand-Pakistan cricket match, where many other students went, and instead had a few drinks at Natalie Hassan's flat.

They went to the Last Moa pub about 10.30 pm, then to Ana's Leith St flat to see her flatmates, before heading to The Cook pub.

They spent the night dancing and Ana was not drunk, Natalie Hassan said.

The two parted some time between midnight and 1 am. Ana was with Mr Roxburgh, who had been at the cricket at Carisbrook Park, and others.

What happened between then and the tragedy was last night unclear, but Baldwin St resident Fred Gordon said he heard the wheelie-bin coming down the street.

"It made a hell of a racket ... It seemed to carry on for quite some time" before there was a sickening crash.

It is unknown how fast the pair were going, or whether they climbed into the bin head-first or feet-first.

Police do not know if anyone else was with them.

Otago University Students' Association president Ayehsa Verrall said she had never heard of students sliding down Baldwin St in wheelie-bins.