INZ Compliance and Verification general manager Stephen Vaughan says they have put New Zealanders at risk by not self-isolating.

"This kind of behaviour is completely irresponsible and will not be tolerated which is why these individuals have been made liable for deportation," he says.

"If they fail to depart after quarantine, they will be arrested and detained under the Immigration Act.

"Being deported has serious consequences. It means individuals will be banned from returning to New Zealand for a period of time and they may also find it difficult to travel to other countries."

He says there's a "good reason" why there are self-isolation requirements in place since it helps save lives and reduced the spread of COVID-19.

"New Zealand is going hard, and going early, to do everything it can to protect New Zealand from COVID-19 and INZ is committed to doing all it can to help protect New Zealand during this uncertain time."

Prime Minister Jacinda Ardern announced the new restrictions on Saturday and they force every person entering New Zealand to self-isolate for 14 days. People arriving from the Pacific Islands are exempt.

"We expect for New Zealanders currently overseas this is a stressful time. We encourage any New Zealander needing consular assistance to contact the Ministry of Foreign Affairs," she said.

Other essential flights will be allowed into New Zealand, for example, if they are bringing pharmaceuticals. Ardern said people should not worry about supermarkets running out of products, as freight will be allowed into the country.

"This is about restricting the movement of people, not products. We will continue to have imports come into New Zealand," Ardern said.