Hyung Soek Lee was sentenced to jail by the Christchurch District Court, but successfully appealed his sentence and will now serve home detention and carry out community service. (File photo)

An overseas student who bit his flatmate 11 times in a "frenzied" attack has won an appeal against his prison sentence.

Hyung Soek Lee, a Korean man studying in Christchurch, assaulted his two flatmates, one of whom was his ex-partner.

About 3am on a Sunday, an intoxicated Lee went into his former girlfriend's room where she was with her new partner, another flatmate.

Lee attempted to strangle the man before biting him 11 times around the cheek, neck and ear, drawing blood and causing large welts. He also tried to gouge the man's eyes.

The man attempted to strangle Lee to stop the biting, which caused Lee to lose consciousness.

Both the man and the woman ran to hide in other rooms. Lee regained consciousness, grabbed a craft knife and went upstairs, yelling "where is he", according to a court summary.

He kicked down the woman's bedroom door and began stabbing the knife into a mattress.

Lee saw his male flatmate on a mezzanine floor and moved towards him. The man, fearing for his life, jumped, falling about three-and-a-half metres and impaling himself on an ornamental vase, causing deep wounds to his buttocks.

He ran from the house while the woman confronted Lee. He pushed her several times and slammed her head into a wall.

Both the man and the woman returned to China after the attack.

The sentencing judge described Lee as "out of control" and "frenzied", which he said would have been terrifying for the victims.

Lee had showed no remorse or empathy for his victims.

The offending justified a sentence of three-and-a-half years in prison, but Lee was given a 20 per cent discount for his age – he was one month shy of turning 21 – and a 25 per cent discount for pleading guilty.

He was ultimately sentenced to two years and one month in jail.

Lee appealed the sentence to the High Court on the grounds that it was too severe, and argued a sentence of home detention should have been considered.

His barrister, Peter Doody, said Lee's apparent lack of empathy or remorse could have resulted from language difficulties. He said imprisonment was unnecessary given Lee would return to Korea after completing his sentence.

High Court Justice Gerald Nation accepted there was "extreme violence" in the attack and the injuries were "quite serious", but determined in relation to other judgments, the starting point for the sentence was too high.

It should have been three years, which – with the discount – made Lee eligible for home detention and community service.

Lee's conviction was quashed, and a new sentence of home detention and 60 hours of community service imposed.