Prime Minister Jacinda Ardern is demanding the names of landlords treating tenants poorly during the coronavirus lockdown.

She said it was "obviously frustrating" to hear about cases where tenants weren't being treated with compassion, but most New Zealanders were doing the right thing.

Ardern said the lockdown was "broadly" running smoothly so far, having only being announced on Monday.

The Government's coronavirus alert level 4 came into effect at 11.59pm yesterday and will be in place for at least four weeks.

Ardern said supermarkets were "generally" orderly and panic-buying seemed to have somewhat subsided.

She reminded people to only shop when they needed to, preferably only one person per household.

And she said people should act as if they had Covid-19.

She thanks nurses, doctors, police and firefighters for their efforts, as well as supermarket workers and bank tellers and cleaners who were also now frontline workers.

Ardern had previously worked at a checkout, and she said it was hard to imagine what they had gone through in previous weeks.

"There will be the odd issue here and there," she said, but the country had started well.

$27m for vulnerable Kiwis

Cabinet has approved a $27m package for social sector groups to help those most vulnerable to deal with the increase in demand for such services during the lockdown.

It would help ensure society's most vulnerable had a place to live and food to eat, and to help those suffering from family violence.

Salvation Army did 3100 parcels last week, with higher demand in Auckland and Northland, she said.

Women's Refuge would also get more funding, and more shelters for victims will be made available, she said.

Ardern said police should be mindful of the homeless, and the $27m announcement should help social services find more temporary support housing, not only for the homeless, but also those seeking refuge from violence.

She said that some ignorance about the lockdown came from the homeless community, which was understandable, and she hoped police would treat them with compassion.

Asked about price gouging, Ardern said Minister Kris Faafoi had already sought assurances from supermarkets that they would not engage in such behaviour.

"That is the degree we are willing to go to ... to ensure New Zealanders are being treated fairly."

Routes to Australia still open

Ardern said the 109 Kiwis on a cruise ship in Perth could still get home using commercial Air NZ flight, even though those flights were not as frequent as normal.

Ardern said Virgin Australia had approached the Government about staff meeting capacity issues in call centres.

Ardern said businesses were offering help and support, and she had appointed former Air NZ chief executive Rob Fyfe to work with Police Commissioner Mike Bush to coordinate private sector help during the lockdown.

How Parliament will work during lockdown

Ardern said Parliament would not sit again until April 28, but a special select committee chaired by National leader Simon Bridges would allow accountability.

The committee will meet on Tuesday at 10am, and will be held remotely.

It is likely to have 11 MPs, with the majority held by Opposition MPs.

$1.5b paid out to Kiwi workers hit by coronavirus

Finance Minister Grant Robertson said as at 9am this morning, $1.5b had already been paid out under the wage subsidy scheme for 244,887 workers; 72,913 applications had been paid out.

He said officials had worked around the clock to process the applications.

The scheme was available to all businesses, he said.

It is designed for employers to make their "best endeavours" to pay workers 80 per cent of their normal wage, and he urged businesses to walk to banks and workers in an effort to prevent layoffs.

Robertson said any business not properly passing on the wage subsidy to workers would be looked into.

He said he would also look into practices around the Government's sick leave scheme for people who were taking leave due to Covid-19, following reports that some workers were being forced to use their own sick leave.

Robertson said it was hard to predict how high the unemployment rate would get to, but it would be much worse than what it was in the GFC.

Some economists have predicted it will hit 30 per cent, but Robertson said there were predictions that were much lower.

The wage subsidy scheme had saved hundreds of thousands of jobs already, he said.

Robertson was looking at a universal basic income beyond the next 12 weeks, when the wage subsidy scheme is set to end - though it may also be extended.

"Income support is going to be an important issue over the coming months."

Fines or jail if businesses stay open during lockdown

Asked about the Mad Butcher being open today, Ardern said businesses could be fined $4000 or see a three to six months' jail if they were improperly open.

She said the Mad Butcher should not be open.

Allowing every food outlet to be open would undermine the goal of the lockdown, she said.

National had this morning asked for greengrocers and butchers to be opened in smaller communities, but Ardern said that dairies and superettes had been allowed to be open to that reason.

"The whole goal for this period is for people to limit contact with one another."

Rents frozen

Robertson also clarified that rent increases were now frozen for the next six months.

Landlords cannot kick out tenants except under limited reasons, he said, such as assaults or threats, or damages a property, or if a tenant is 60 days behind in rent payments.

He said feedback from the business community about commercial landlords being inflexible about rent payments, and he urged those landlords to be more flexible.