New Zealand should only support Australia's bid for a seat on the United Nations Human Rights Council if it improves its treatment of detainees, say the Green Party co-leader James Shaw.

Photo: 123RF

Mr Shaw said it was not just New Zealanders who were being mistreated, and New Zealand should use the opportunity to force Australia's hand.

"They should halt the automatic deportation and should review every case and they should bring back the detainees that are on off-shore detention centres back on to Australian soil."

Labour MP Kelvin Davis said the Government should use Australia's bid for a seat on the council as a lever to get a better deal for New Zealand detainees.

Last weekend New Zealand Prime Minister John Key met with his Australian counterpart Malcolm Turnbull and discussed the new deportation policy across the Tasman.

Under the law change, which came into effect December, non-citizens can be deported if they have served more than a cumulative year in prison.

Some have lived in Australia from an early age, and nearly 200 are in detention centres waiting for decisions on their deportations.

John Key has said he expects about 1000 New Zealanders could be sent back as a result of serving jail sentences of over a year in total.