Police figures show 660 New Zealand passport-holders were removed from Australia between January 1, 2015 and January 19, 2017.
It's expected around 840 more are on their way.
Cahill says many of the new arrivals are joining gangs that deal in methamphetamine, increasing competition and in the process, the risk of violence.
"With any business there's competition around your market.
"With gangs the way they deal with competition is to start fighting. In Australia we've seen some significant gang violence, shootings, murders.
"The risk is the new arrivals could bring that level of violence here."
Cahill says the police and government have recognised the problem and are acting.
"We're not putting our heads in the sand. We have 80 more organised crime staff and they are doing everything to deal with the problem before it gets out of control.
"When you understand the issue, you've got a much better chance of dealing with it.
But the gangs are well established and there's a lot of money involved.
"It isn't going to be easy and it's going to take a lot of hard work."