Fergus Watts after his court appearance for streaking earlier this year.

A student who sliced his buttocks after a falling off a roof at a rowdy Christchurch party streaked during a Cricket World Cup match earlier this year.

Fergus Watts, a University of Canterbury engineering student, remains in Christchurch Hospital "stable and doing well" after he fell through glass on Karamu Pl, Riccarton on Friday afternoon.

READ MORE: * Man seriously injured after falling through glass

DAVID WALKER The Karamu St house where Fergus Watt fell off a roof and injured his buttocks.

He declined an interview on Saturday and his friends were apparently under instruction not to talk about it.

It was reported he suffered serious injuries to his buttocks and legs, while 3News quoted an unnamed ambulance officer saying he "almost completely sliced his buttocks off".

Earlier this year, Watts was arrested after streaking at a Cricket World Cup match between England and Scotland in February.

Watts, who is in his final year of study and an Engineering Society of Canterbury (ENSOC) media and marketing executive, was discharged without conviction over the streaking incident, arguing it would affect his burgeoning career as a professional hockey player.

His June court hearing was told he was sober, but egged-on by his friends when he streaked during a break in play, when Scotland had no chance of winning. Watts paid a $750 donation to the Westpac Rescue Helicopter Trust for what his lawyer described as "tomfoolery".

Hundreds of people attended the annual house party where Watts was injured, organised as a pre-event or alternative to the university's sold-out end of lectures Tea Party.

A party house occupant declined to talk about the accident on Saturday, but said Watts was "in a bad way".

Watts, 21, had left his phone at the flat, he said, as had several other partygoers.

The party, which went from about 7am until after midnight, spilled into at least two other surrounding properties.

Watts fell about 12.15pm, before the party hit its peak.

Neighbour Hadon He said he came home at 10.30pm to see the party still in progress, but said there was no talk of an accident.

"I don't know what happened," he said.

"When I came home the music was still going and taxis were arriving but that was all."

An occupant of another party house in the street, who did not want to be named, said there was confusion about what happened.

She was aware of the accident, but only knew the details from media reports.

Acting Senior Sergeant Ayson Williams said earlier that police understood Watts to have fallen off a roof and through a window, but circumstances were yet to be confirmed.

Police happened to be in the area at the time of the incident, he said.

Karamu St is notorious for hosting a street party before the university event.

Police arrested three young people disorderly behaviour on Riccarton Rd before the Tea Party event.

"We have noticed there has been a lot of pre-loading before this event . . . intoxications levels [were] higher than last year," Inspector Peter Cooper said.

Students without tickets tried in vain to get into the event. Some were spotted crawling beneath a fence, while others try to camouflage themselves in line, hoping they wouldn't be noticed.