Refugees from Nauru have pleaded with New Zealand Prime Minister John Key to resettle them, despite an agreement between the Key Government and Australia expiring.

Key points: NZ offered to take in 150 refugees from the Nauru and Manus Island

NZ offered to take in 150 refugees from the Nauru and Manus Island Aus-NZ inked refugee deal during Gillard era

Aus-NZ inked refugee deal during Gillard era Places given to Syrian refugees after Australia did not take up the offer

Places given to Syrian refugees after Australia did not take up the offer Refugees plead with NZ PM to take them in

New Zealand had offered to resettle 300 refugees as part of a two-year deal with Australia, signed in 2013 by former prime minister Julia Gillard.

At the time, Ms Gillard said the deal could affect asylum seekers currently being held in processing centres on Manus Island and Nauru.

The plan had been proposed to begin in 2014, with the annual resettlement of 150 refugees contributing to New Zealand's overall intake of 750 places each year.

But a spokesperson for New Zealand Immigration Minister Michael Woodhouse said Australia has not taken up the offer and the resettlement places had instead been given to Syrian refugees.

Former prime minister Tony Abbott quashed the plan after taking government in 2013, saying the message to people smugglers had to be "crystal clear".

In a joint address with Mr Key, Mr Abbott said that any people arriving illegally by boat would be sent to Nauru or Manus Island.

"People ought not think that New Zealand is some kind of a consolation prize if they can't come to Australia," he said.

New Zealand's shadow foreign affairs spokesman David Shearer said on Tuesday that the deal was never a good one.

"[New Zealand Prime Minister] John Key agreed that Australia could resettle 150 of their refugees on condition that if any boat people were coming to New Zealand then Australia would intercede," he said.

The Greens have belatedly criticised the Coalition Government for not taking up the offer.

Senator Sarah Hanson-Young said it was ridiculous for the Government to "dump" people seeking asylum in Cambodia instead of countries such as New Zealand.

"If the Government was actually interested in resettling people and letting them rebuild their lives it would have leapt at this opportunity," she said in a statement.

"Instead they have chosen to continue to punish men, women and children for seeking a better life."

Further comment has been sought from Immigration Minister Peter Dutton.

'They say we will never be settled in Australia'

The new criticism comes as refugees from Nauru plea with Mr Key to take them in.

In a letter, confirmed by the New Zealand Government, 28 refugees said that Australia would not accept them "despite us asking them for safety".

"They say we will never be settled in Australia," it stated.

"They gave us to the Nauru Government and told us we were now their responsibility. Nauru has not given us and does not have the means to give us permanent protection or safety.

"After 30 months in mouldy tents and now in the community where we are not accepted, some of us now have travel papers which give us the freedom to leave."

The letter states that the 28 signatories have all had their claims processed and are considered refugees.