Prime Minister John Key says the Government will continue to lobby Australia over citizenship for future arrivals.

But for now he is happy with yesterday's limited win and congratulated Australian Prime Minister Malcolm Turnbull for his leadership on the issue.

Mr Turnbull announced a new income test, allowing about a third of the 305,000 New Zealanders who settled in Australia after February 2001 to gain citizenship if they earned A$53,000 ($57,000) for five consecutive years.

"It is in recognition of the advocacy that John Key has made on behalf of the many New Zealand citizens in Australia who are working here and are part of our community," Mr Turnbull said.


Others arriving in Australia from today will have to use other skilled migrant categories to gain citizenship.

Mr Key said he would continue to advocate for future arrivals and that Mr Turnbull had given an indication Canberra would continue to look at it.

"They have got a big batch of people they are going to have to process over the next few years - potentially up to 100,000.

"Yes it would have been great if they had made it from February 2001 going forward forever but I think they wanted to quarantine the numbers in the sense that we will see how it is all working ... get a sense of what it all means."

The pair's political and personal closeness was on display yesterday, not just through the so-called "pyjama diplomacy" in which Mr Turnbull and his wife Lucy are hosting the Keys for the weekend.

Mr Turnbull introduced Mr Key to a lunch in Sydney for over 700 in the most effusive terms. He praised what he described as his ability to "govern from the centre", to understand what people wanted, to move quickly and simply on such areas as broadband, on trade and other areas.

"He is a great role model to me and any other leader."

He said Australia could learn a lot from New Zealand. "We in Australia do not pay enough attention to New Zealand."

Asked about the deportation of Kiwi criminals from Australia if they have been sentenced to more than a year in jail, Mr Turnbull said it was law that had been passed with the agreement of the Opposition in 2014. And it applied equally to all countries.

"It is not targeted at New Zealand. I know it may look like that," he said. And detainees could return home to appeal the revocation of their immigration status without prejudice.