Wellington came to a virtual standstill on the first day of the nationwide lockdown on March 26.

Police Commissioner Mike Bush says Kiwis will be greeted by the "friendly face" of police during New Zealand's four-week lockdown. But a national state of emergency means the police now have broad and discretionary powers unseen since the 1951 waterfront strike. Thomas Manch and Collette Devlin explain the hard power behind the soft message.

Damian Christie had a run-in with a police officer while working for an essential business on Friday, day two of the lockdown.

The former broadcaster was delivering video equipment to a client's business, letter in hand to prove he was essential. He says the client, a large food producer he declined to name, needed the video gear to share coronavirus-related messages with its staff around the country who will continue to work.

On his way home, a policeman on a motorbike pulled up alongside him and asked what he was doing. Christie said the officer was not satisfied with the answer, saying he should only leave the house for medical supplies.

ABIGAIL DOUGHERTY/STUFF Police pull cars over on Tamaki Drive in Mission Bay checking if people are adhering to the nation-wide lockdown.

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"He was basically yelling, and I was like, 'I've got a letter', and he didn't care. It just sort of shook me." He said the officer's interpretation of the rules seemed incorrect and overzealous — what about going to the supermarket?

"[The rules are] so arbitrary, you're hearing one thing from the Prime Minister and one thing from the Police Commissioner," he said.

Can you take a five minute drive to your local beach? But can you swim? The questions began days before New Zealand entered a four-week lockdown — welcome to day four — and haven't stopped being asked since.

As police officers patrol mostly-empty streets around the country, New Zealanders have been criticised by their peers for looking for loopholes. But there's another reason for the confusion.

New Zealand has become a police state for at least four weeks. Police Commissioner Mike Bush has routinely said people can expect to see the "friendly face" of the police, but behind the soft messages is a hard power.

Officers can now enter your home without a warrant to look for gatherings. There's the power to detain, seemingly indefinitely, if you continue to leave the house without good reason.

Legal and policing experts say that, under this national state of emergency, police powers have been expanded in a way unseen since the 1951 waterfront strikes. And the control over Kiwis - and activities like going for a walk - is broad, discretionary, and so far poorly defined.

STUFF Former broadcaster Damian Christie, pictured here hosting Back Benchers, says he's concerned about how police are enforcing the lockdown after a run-in with an officer.

Otago University public law professor Andrew Geddis said police could now use "extreme and unprecedented" powers to stop people from being around others — which has constrained the freedom of movement guaranteed by the Bill of Rights Act.

But there was an unclear line between these constrains - which should only apply to the "extent necessary" to prevent the virus spreading - and the permitted outdoor exercise and trips to essential service.

Geddis offered two examples to illustrate the predicament. If an officer challenged him for walking further than their own street – this was arguably power taken too far. If he argued, "I could find myself in the back of his paddy wagon".

Message to those congregating outside during the lockdown: 'Don't be stupid'.

But another officer could be satisfied with a person walking two kilometres from their home. "All of a sudden my life and what I'm allowed to do, comes down to which officer happens to talk to me at that time."

Police staff may have been instructed on how to apply the powers, he said, and such instruction should be made public.

"We ought to have some idea of what those controls are. So we can know with clarity what it is we can and can't do."

Police Association president Chris Cahill said there remained a lot of unknowns about police's new powers, and officers needed clear direction.

"The challenge is, there are a lot of exceptions to the rules. There are a lot of reasons for people to be out and about and there is some confusion out there as to what they can and can't do ... it is difficult to police."

Stuff has asked police to list the specific charges and punishments that people could face, if instructional guidance has been provided officers, and whether it could be made public to provide clarity.

A police media spokeswoman provided a statement that echoed Bush's comments this week, saying police had a number of powers under the relevant legislation.

A four-step process would have officers first educate people, then give a warning, then arrest and detain for a short period. Only serious and persistent breaches would be prosecuted.

Victoria University of Wellington criminology lecturer Trevor Bradley said police's ability to enter homes, unimpeded, to break up gatherings was among the most powerful under the current setting.

"Previously there were legal safeguards for citizens ... a lot of those go by the wayside now under these various provisions."

The new powers were a practical and symbolic response to let people know the national emergency would be enforced, he said, and would not be used for non-coronavirus related matters. Any court would likely disregard evidence obtained improperly under such powers.

Bradley said police had made clear there would be limits. People detained for breaching the lockdown could expect a "cooling off period" in the cells, not indefinite quarantine.

"One would hope that the police take a very softly-softly approach, particularly in the first instance, because the stakes are quite high for police here ... Unreasonably heavy handed approaches by police, you know, could affect the public sense of trust and confidence."

But justice advocate Julia Whaipooti was not reassured. She said, though the enforcement of the lockdown was needed, there was concern about a heavy-handed approach, particularly for communities such as Māori that don't have "high trust" relationships with police.

"There's one thing to say, '[the powers] will be used for this purpose'. But we know bias exists within policing, and that also provides a tool to access places that otherwise, under normal circumstances, it would be really hard to get.

"How are police monitoring their own behaviour? How are they recording when they decide to go into houses?"

Independent Police Conduct Authority general manager Warren Young said the authority remained open for business, and would keep a close eye on police during the coronavirus emergency.

"We encourage people who have concerns to contact us," he said.

Powers And Punishments

Some of the explanations for how police will enforce the lockdown have shifted quickly this past week. On Thursday, Bush told RNZ that roadblocks for monitoring people's movements were not going to be in place.

Such checkpoints were being run by police in Hamilton and Christchurch on Friday, picking up on people with various "abysmal excuses" for leaving home, such as a half-hour drive to a supermarket, a 20km trip to walk the dog, and a man going to visit his girlfriend.

Such freedoms cannot be enjoyed under lockdown. Bush has said that people who ignore warnings will be "having a little trip to our place" — meaning they will be detained. He would not specify how long such detainments would last.

Police will prosecute serious breaches, and the first person was charged with flouting the rules.

James Gordon Beadle on Friday fronted the Auckland District Court on a charge of failing to comply with a direction from the medical officer of health, which carries a maximum sentence of one year in prison. He was also charged with failing to stop for police, and driving while drunk or under the influence of drugs.

Here's a run down of the powers police have to control the pandemic.

ROBERT KITCHIN/STUFF Police patrol Wellington's city centre disobeying the lockdown order.

Health Act 1956

On Tuesday the Director-General of Health Ashley Bloomfield issued a section 70 Health Act Order.

The order required all premises to close until further notice, and forbids people from congregating in "outdoor places of amusement or recreation of any kind of description".

Police are an enforcing agency, and can charge people for ignoring the order.

Victoria University associate professor of law Dr Dean Knight said the section 70 notice, which was only disclosed on Friday, provided a strong legal footing for the lockdown but was not bespoke.

It did not reflect different signals and advice coming from the press conferences around issues such as whether a person was allowed to go to the beach.

There was a layer of coercive power, police telling people to "do the right thing", on top of the hard legal regime," Knight said.

KEVIN STENT/STUFF Mike Bush, Commissioner of Police, says officers have already come across people not complying with the lockdown.

Civil Defence Emergency Management Act

A national state of emergency was declared on Wednesday, meaning aspects of the Civil Defence Emergency Management Act came into force.

The law empowers police to enter, and if necessary break into, any premises or place under the belief that the action is necessary for saving life, preventing injury, or rescuing and removing injured or endangered persons.

In the context of coronavirus, saving lives has been determined as keeping people apart - preventing the transmission of the virus. Meaning if police believe people are gathering in a home, they may enter without a warrant to investigate.

Whaipooti said this power was particularly concerning as it may have officers suspicious of Māori and Pasifika families, who often have many family members living in the same home.

The act also has a catch-all provision that allows for other actions to "relieve suffering or distress" - this is not further defined. Roads can be blocked, towns and cities can be cordoned off.

Under section 91 of the law, police can also direct any person to stop any activity that may contribute to the emergency, or limit the emergency— in this context, that includes leaving the home unnecessarily.

Knight said: "That power is a big box ... That's a big fat discretion."

Geddis said previous national states of emergency, such as during the Christchurch earthquake, have only been regionally applied.

"This I think you could genuinely say is the first time that New Zealand's emergency powers have been used in a way that affect literally everyone in the country. There's no hiding from it," Geddis said.

Summary Offences Act

Bush, during an earlier press conference, said people breaking the lockdown rules could be charged for obstructing a police officer under the Summary Offences Act.

The charge, which is available to police usually, can carry a three to six month prison term.

What Can I Do?

Government controller John Ombler on Saturday attempted to clarify what had been confusing many about the lockdown.

"We don't want people congregating at parks and beaches. Keep to the two metre rule ... Don't go swimming or surfing. A walk along the beach is fine but don't do anything that may result in you needing help," he said.

Emergency services were needed to respond to the coronavirus challenge, not sporting or recreational incidents, he said.