An Australian political commentator says the law is the law when it comes deporting criminals back to New Zealand.

Prime Minister Jacinda Ardern is calling on Australia to only send criminals back here if they have 'genuine' Kiwi connections.

Figures show 25 percent of those returned here reoffend.

Australia's policy changed in 2015 so that anyone not an Australian citizen and who has served more than a year in prison, is deported.

Peter Fitzsimons told Mike Hosking citizen rules apply even to those at the top.

"Like Barnaby Joyce, it's ludicrous, we all acknowledge it's ludicrous because we all know he's absolutely Australian, technically he's a kiwi so we have to go through the whole polava of a by-election. Surely it also has to happen at the lower socioeconomic levels as well."

LISTEN ABOVE AS PETER FITZSIMONS SPEAKS WITH MIKE HOSKING