John Key says the offer to take 150 boat people from Australia as part of New Zealand's refugee quota came from him, and was not made under pressure from Australia.
"I have been firmly of the view we should do this deal," he said on the way to National's weekly caucus meeting.
"It wasn't pressured by Australia. We are not trying to help them out, we are not trying to ingratiate ourselves with the Australians.
"There's a pretty clear rationale behind what I'm doing. One is we don't take more people, two I am pretty ambivalent (sic) about where they come from."
Key said the deal also allowed New Zealand to "hook into their technology, their systems and their people for which we don't have anywhere near the capability they have".
The best way to stop boats coming was to intercept them before they left their country of origin, he said, adding: "We can't do much when they are on the water."
The deal would also stop the situation where a boat turned up in Australia heading for this country and Australia "shepherded" it across the Tasman.
That had been a possibility with a previous boat, but Key said Australian Prime Minister Julia Gillard had not raised that with him.
"It comes from my intelligence sources," he said.
"I have a big network that informs me and educates me on what's going on."
Labour leader David Shearer said Key was trying to justify a bad deal - but could not guarantee Labour would reverse the policy if elected.
Every day Key was producing a different reason for why New Zealand needed to take 150 Australian refugees, he said.
"Where is this intelligence? This is an incredible claim ... front up with the evidence, we want to see it."
"He needs to come forth and show us some of this intelligence. I don't believe that this intelligence is so top secret that it needs to be hidden from New Zealanders."
Shearer said if elected, Labour would discuss the policy with Australia.
Key said the offer also opened the way for New Zealand to send refugees that arrived here to Australia's offshore processing camps, which would be a strong deterrent to them coming to this country.
While it was difficult for refugees to sail to New Zealand it was possible to sail around the world in very small yachts, so it was fanciful to say they could not get here in a steel-hulled boat.
Asked about conditions in the camps and international criticisms of them, Key said: "I haven't inspected the camps obviously but I accept the prime minister at her word."
He had raised the issue with her.
"Our expectation is that the camps would be at the world standard we would expect from a developed economy like Australia," Key said.
It was likely New Zealand would draw most of the 150 refugees from camps on Australian territory not from Nauru or Papua New Guinea, he said.
But Shearer said the Australian camps were not held up as good models.
"Why can't we handle the boat people that come to New Zealand in New Zealand, and how many boat people have come to New Zealand? Zero," he said.
New Zealand should have reserved the right to chose where its refugees came from so they could take the most needy, he said.
"We've given up the right to chose the people that could come to New Zealand," he said.
Green Party immigration spokeswoman Jan Logie said the strength of multiple damning international reports on Australia's policy meant Key needed to see the conditions in the offshore detention centres first-hand, instead of relying on Gillard's word.
"The Government needs to take a stand against this inhumane Australian policy, not adopt it for its own use," Logie said.
"New Zealanders rightly expect that people seeking asylum from hardship be treated with respect."
- Fairfax Media