Why Ron Brierley is extremely unlikely to be deported as a 501 to New Zealand

Sir Ron Brierley leaving court in Sydney after pleading guilty to child pornography possession yesterday. Photo / Liam Mendes

Disgraced New Zealand-born businessman Sir Ron Brierley is extremely unlikely to become a 501 deportee after guilty pleas to possession of child sexual abuse material - because he is an Australian citizen.

Brierley, a Wellington College old boy, pleaded guilty to three of 17 charges during a Sydney court hearing yesterday morning. One charge to which Brierley admitted identified the offending material as including images of children ranging in age from 2 years through to 15 years.

The case was set down for a fresh hearing on April 30, although it was unclear if that was when sentencing would take place.

Despite his offending, Brierley seems unlikely to be added to the hundreds of New Zealand-born Australian residents who have been deported from Australia to New Zealand for crimes committed - people widely known as 501s, the character section of the Australian Migration Act that allows the cancellation of their visa.

Tensions over the 501 debate have been clear between Prime Minister Jacinda Ardern and Australian Prime Minister Scott Morrison. Photo / Penny Bradfield

A person's visa can be cancelled or refused by the Australian Department of Home Affairs if it is believed they do not pass the character test. Any non-citizen sentenced to 12 months prison in Australian was subject to deportation - even if they served their time behind bars in the past.

Christchurch 501 advocate Filipa Payne explained Brierley wouldn't be deported as a 501 due to his citizenship.

"[Brierley] is an Australian citizen who can not be placed through the deportation regime, unless they revoke his citizenship," she said.

Payne speculated Brierley's citizenship would only be revoked if he was linked to terrorist activity, similar to 26-year-old Suhayra Aden who had her Australian citizenship revoked when her ties to terrorist group Isis came to light in February.

Hypothetically, Payne was confident if Brierley was not a citizen of Australia and merely a visa-holder, his crimes could warrant deportation.