However, Mr Poole said the arrival of the boat in Australia reflected Mr Key's "bad decision" to enter the agreement, which he said was attracting more asylum seekers to this part of the world.
"This is precisely what we predicted. Unfortunately what our Government has done is they've actually fed into the whole problem in Australia."
No boat has ever made it to New Zealand and it was unlikely to because of "treacherous" conditions in the Tasman Sea.
"But what it's done, it's now acting as a magnet, the particular policy, because he's now accepting 150 out of their camps. We've become part of Australia's problem," said Mr Poole.
New Zealand is part of the United Nations convention, so if a boat made it here, the Government would be obliged to process the cases and determine if those aboard were genuine refugees.
The group that arrived in Australia, believed to have travelled for more than 40 days from Sri Lanka, would have endured hazardous waters and conditions that endangered their lives, Mr Poole said.
"They would have been low on food, there would have been potential medical problems - they're taking huge risks."
If asylum seekers did manage to cross the Tasman, New Zealand would be obligated to provide help if the vessel got into trouble within the country's search and rescue area.
It is believed to be the first boat to have travelled so far south in recent years. Most asylum seekers arrive near Christmas Island, more than 2000km north, where they are usually intercepted.
If found to be credible asylum seekers, they will be given a visa for Australia.
New Zealand Customs has been in discussion with Customs in Australia over the 66 boat people in Geraldton, said a spokesman for Immigration Minister Michael Woodhouse.
The outcome depended on whether they asked for asylum in Australia.
The passengers could not ask for asylum in New Zealand while in Australia, he said.
It is unclear whether they could be the first to be processed in New Zealand under the new agreement with Australia, if they are granted refugee status.
Mr Key said Australia was receptive to processing any mass arrival to New Zealand in its offshore centres in Nauru and Papua New Guinea, in exchange for accepting the 150 Australian-approved refugees.
The passengers included four babies and a pregnant woman.
The men from the boat are being taken to a separate detention centre from the women and children, before the group are all processed on Christmas Island where they will receive health and security checks.