Immigration Minister Michael Woodhouse hasn't ruled out the possibility of a mass arrival by boat of asylum seekers into Northland in the future - orchestrated by people smugglers.
However, he said the Government passed legislation and introduced new policies last year to help deter, penalise and manage a mass arrival if it occurred.
The minister was responding to reports that an attempt by people smugglers carrying 50 asylum seekers from Afghanistan, Pakistan, India and Bangladesh to travel 8000km to New Zealand in a boat was thwarted by Indonesian police last week.
They are currently detained in Indonesia and their plan was reportedly to land on the uninhabited Three Kings Islands off Cape Reinga or somewhere near Kaitaia.
Mr Woodhouse said the Immigration Amendment Act enabled mass arrivals to be detained for up to six months and allowed District Court judges to extend detention periods for up to 28 days at a time.
"Those posing a high security risk could be detained in a Corrections facility, but the majority would be expected to be sent to the Mangere Refugee Resettlement Centre (Auckland)," he said.
Detention periods allowed agencies time to confirm identities of asylum seekers, and assess whether they posed a risk to national security or public safety.
"There's no doubt that New Zealand is a growing target for people smugglers and a mass arrival at some stage is a very real possibility that we need to be fully prepared for."
An assessment for biosecurity risk and initial health screening for passengers and crew was normally undertaken for any vessel that arrived into the country.
Customs confirmed it carries out air and sea patrols of New Zealand waters to prevent the smuggling of drugs, weapons and flora and fauna.
The busy periods for Northland coastal patrols were September to December when yachts arrive and April to July, when they depart. Customs carries out regular air and sea patrols outside of these times.
The patrols included utilising New Zealand Defence Force assets to ensure small crafts and other vessels arriving in New Zealand adhere to New Zealand's border entry requirements.
Kaitaia-based Labour MP-in-waiting Kelvin Davis said it was too dangerous for asylum seekers to travel thousands of kilometres and come to Northland. On the possibility of seeking shelter at Three Kings Islands, he said: "That's a stretch. The rugged, sheer cliff on the island will make it difficult.
"I think there's a bit of scaremongering to generate a bit of anti-boat people rhetoric.
"We need to let cool heads prevail," Mr Davis said.
However, if asylum seekers managed to arrive on Northland shores by boat, he was confident Immigration and Customs had processes to deal with them.
President of Whangarei Coastguard, Dave Gray, who has worked as a marine engineer on passenger cargo vessels in high seas, said the ambitious journey was possible but extremely hazardous.
"The vessels they (people smugglers) use are not purpose-built by any sort of imagination and the larger they are, they tend to be overloaded to a point where it becomes unstable and all it needs is inclement weather or rough seas to add to their woes."
Mr Gray said old wooden boats measuring between 40 and 60 foot in length were typically used by asylum seekers.
He didn't believe New Zealand was either ready to guard its borders or to cope with a sudden arrival of asylum seekers.