A criminal being deported from Australia for "barbaric and brutal offending", has warned he'll join a gang in New Zealand and continue offending.

Silao Robert Termorthy Sau went to Australia in 2009, but had been in the country less than a year when his violent offending started.

He's now been ordered to leave Australia because of his violent behaviour, including assaults, multiple counts of armed robbery, arson, recklessly causing serious injury, as well as other more minor charges.

Many of the victims were of Asian origin, with some of the assaults seemingly planned.

Sau said he would be pressured to join a gang if he's sent back to New Zealand, and wouldn't have any family to support him.