Key made the announcement at the end of talks with visiting Australian Prime Minister Julia Gillard whose government last year faced a record number of more than 17,000 asylum-seekers arriving by boat.

"People smuggling has tragic consequences. It is a regional problem that requires regional cooperation," Key said, adding Australia had assisted New Zealand in the past.

"There are boats that we can point to that were on their way to New Zealand where Australia has effectively taken those people."

Gillard warned New Zealand's assistance should not be seen as a message of encouragement to boatpeople and Australia would continue to rigorously patrol its waters.

Most of the asylum-seekers pay people-smugglers for passage from Indonesia on over-crowded, leaky, vessels, and sinkings are routine.

"Australia expends a lot of effort in detecting and disrupting people-smuggling ventures and prosecuting people-smugglers. This is transnational crime and we take a very rigorous approach," she said.

The 150 boatpeople to be taken by New Zealand would be people who have been approved as refugees in one of Australia's offshore processing centres, in the island state of Nauru or Manus in Papua New Guinea.

Key said they would be part of the annual quota of 750 refugees New Zealand takes as per its commitment to the United Nations High Commissioner for Refugees (UNHCR).

"They will not be in addition to the quota. We are limiting this to 150 in order to still maintain a significant commitment to resettling refugees referred by the UNHCR," he said.

New Zealand last took refugees in a similar manner in 2001 when it resettled 131 of the 438 boatpeople rescued by the Norwegian freighter Tampa near Christmas Island, an Australian territory in the Indian Ocean.