Immigration lawyers say more people are being deported for minor crimes, even though the number of criminals being thrown out of the country after serving a prison sentence has fallen.

They say Immigration New Zealand is now turning its attention to those committing crimes that do not land people in prison.

Photo: RNZ / Lauren Baker

Ninety-seven people were deported in 2010 after having served a prison sentence. That number has fallen gradually since then, and stands at 48 so far this year.

But a principal of the law firm Ryken and Associates, David Ryken, said Immigration New Zealand was now taking a firmer stance with people whose offending never sent them to prison.

"In the past, a small matter might not have attracted a decision of an immigration officer. Now it seems to us that every minor matter is progressed," he said.

Mr Ryken said that included minor assaults and theft, which often only garnered a fine or community work.

He said Immigration New Zealand had been able to deport people for such crimes for many years - but had only started doing so recently.

Mr Ryken said this country was following what he called Australia's "negative attitude" to immigration. He cited one example in particular.

"A deportation liability notice was served on the basis of an offence that led to just 100 hours of community work. Obviously the court didn't think it was that serious. He appealed against the [deportation], the appeal was unsuccessful, and the person will be deported."

Another immigration lawyer, Aaron Martin, put the increase down to Immigration New Zealand improving its own procedures, and a greater focus on complying with its own rules.

But Mr Martin said the law should change because the bar for deportation was too low.

"Making people liable for deportation in circumstances where the court has the power to impose three months of imprisonment, even though it may be a level of offending that only results in a fine, I think is too low a threshold," he said.

Association for Migration and Investment director Simon Laurent said the threshold for criminal deportation effectively included every non-trivial offence.

He said immigration authorities were just using the tools available to them - but said the law was too heavy-handed at times.

"In a lot of cases, I think it's using a hammer to kill a snail. It's over the top for the type of offence these people have committed. But the law allows it, and Immigration New Zealand is entitled to use it."

Immigration New Zealand said each case was considered on its own merits - but people with criminal convictions were most likely to be deported.

It said people could appeal their deportation notices to an independent tribunal.