Since the lockdown began last Thursday, three people have been arrested by police for "persistent breaches" of the requirements. Two have been released without charge, while the third remains in custody with other "outstanding matters in front of him".

While it's unknown what exact rules that trio broke, police are frustrated by some Kiwis and tourists continuing to drive around without explanation.

Police Association President Chris Cahill said while most people were complying, others "don't seem to get the message".

"It is pretty simple really. If you don't need to leave your bubble, stay home. You don't need to get in your car unless you are going to the supermarket, to the medical centre or something like that, otherwise, it's on foot around your neighbourhood," he told The AM Show.

Police Commissioner Mike Bush has previously said while officers are primarily on the streets to educate people about the new rules, arrests will be made if people continually flout the requirements. Having a relatively soft initial approach to rule-breakers is justified, Cahill said, as people get used to living under the lockdown.

One way to ease the pressure on officers, who are also having to deal with regular crime such as family harm, could be to introduce a nightly curfew, Cahill said.

"[There are] people driving around at night. In general, there isn't that many who should have to do that at night," he said.

"So we are just wondering whether [we should] put a curfew on people travelling at night to make it that much easier for police."

He said those essential workers who are required to be out at night would be exempt.

"The people who are out after that are either very genuine... like truck drivers or things that are delivering what we need to get out there. But the majority of people in vehicles after that probably shouldn't be out and we are finding a lot of them, unfortunately.

"They have all got pretty stupid excuses, most of them, a lot of them just plead ignorance. Police are being really softly, softly about it. They are giving people a chance."

While the lockdown protocols are in place to limit people's exposure to the virus, which has infected more than 500 people in New Zealand and killed one, police and other emergency workers are on the frontline against the invisible enemy. Cahill said officers are frequently considering how to keep themselves safe.

"It is a real challenge for police in a small vehicle, obviously when they get so close. It is a matter of having a lot of personal care around your cleaning, your washing, cleaning the vehicle before they get in," he said.

"It just highlights how difficult [it is] for emergency services who have to be out there working at this time. It's tricky for them.

"The problem with policing is if you knew what you were dealing with all the time, you could put all your gear on, your personal protection gear, your mask, your gloves, but so often, policing, you don't know what you're dealing with until the roughs in front of you."

Two police staff have contracted COVID-19 and are now in isolation. The two cases are "very separate" to each other, according to Bush, who doesn't believe there is a cluster within police.

"We're always very concerned about our staff - ever since this [the virus] kicked off, we've been working on building a contingency, so we've got a contingency plan in place."

Bush said the police are looking at how other countries are responding to the pandemic to inform their own response.

"We're even looking as far as what's happening inside the NYPD and taking learnings from other organisations."