A major exercise to prepare for a mass arrival of asylum seekers by boat will be launched by government agencies on Tuesday.
The eight-week exercise, headed by the Customs Service and Immigration New Zealand, includes a series of planning exercises before a simulated mass arrival at Devonport Naval Base next month.
Immigration Minister Nathan Guy announced the launch of the exercise on Monday, alongside the introduction of new legislation to allow the mass arrest and detention of asylum seekers.
"The aim is to make sure New Zealand is fully prepared to respond to a mass arrival by sea of potentially illegal immigrants," Mr Guy said.
"We know that New Zealand has been a target in the past for people smugglers, and we need to be prepared for future attempts."
The exercise will start from the first notification that a vessel is on the way, through to processing and accommodating asylum seekers while their claims to asylum are determined.
The Defence Force, police, and ministries of health, education, foreign affairs and corrections are among a number of other agencies involved.
Mr Guy says the arrival of 10 Chinese asylum seekers in Darwin last month, who said they were on their way to New Zealand, proves the need for new laws.
They eventually decided to seek asylum in Australia, but they had been prepared to risk trying to sail the Tasman in a fishing boat to try to reach New Zealand.
Announcing the new legislation, Prime Minister John Key says there's no indication a boatload of illegal immigrants is on its way but it could be only a matter of time.
Under current law they could only be arrested on individual warrants - and Mr Key says that's a problem.
"We're moving into line with Australia and we're sending the message to people smugglers that they shouldn't be in the business."