Prime Minister Jacinda Ardern praised New Zealand's lockdown efforts, as Northland police were kept busy checking on potential lockdown breaches over the Easter Weekend.
Covid-19 testing may be ramped up in Northland due to its high Māori population, which is at higher risk of the deadly virus.
The number of Covid-19 cases in Northland is at 26, with one new case yesterday, but the country has suffered its fifth death from the virus.
Director-General of Health Ashley Bloomfield said there were 19 new cases of Covid-19 in New Zealand as of 9am yesterday - up one on the 18 cases the previous day.
Fifteen of the news cases are confirmed while four were probable cases - taking the national total to 1349 cases, with 546 of those now fully recovered from the virus.
Northland's case total is now 26. There are no cases in Northland hospitals with 19 self-isolating at home and seven have recovered.
Of Northland' s confirmed cases seven are Māori, 17 European, one Pacific and one Middle Eastern/Latin American/African.
On Sunday 26 people were swabbed at a Community Based Testing Centre (CBTC) in Northland and there have now been 1665 tests carried out at a CBTC. This figure does not include tests done by a GP or in hospital.
Bloomfield said there are 15 people in hospital, an increase of one from Sunday. The total includes four people in ICU – one each in Wellington, Middlemore, Dunedin and North Shore hospitals. One of these ICU patients – in Dunedin – remains in a critical condition.
He said 1660 tests were processed on Sunday, with a rolling seven-day average of 3230 and total tests to date of 62,827.
''We anticipated a drop off in testing over the Easter holiday period. Partly this is due to the effect of public holidays, and also with the measures in place around alert level 4, we would expect fewer people to be presenting with respiratory issues,'' Bloomfield said.
''We will be increasing testing again this week and we're well placed to do more testing across the country.''
He said more testing would be done in regions that have high Māori populations, such as Northland, as Māori were more susceptible to serious harm from Covid-19 than the rest of the population.
Prime Minister Jacinda Ardern said despite the lockdown, she hoped New Zealanders were enjoying their Easter break. She said New Zealand is not in a position to move out of level 4.
Ardern praised New Zealand's lockdown efforts, but said there is more to go: "Please stay home."
Meanwhile, Northland police were busy over the Easter weekend following up on calls from members of the public who reported breaches to the lockdown rules.
Senior Sergeant Pat Davis welcomed those reports saying that between Friday and mdday Monday police responded to 96 pandemic-related callouts and conducted 18 self-isolation checks on people who recently returned from overseas. Police also visited 134 premises, including supermarkets, to ensure "people are behaving", Davis said.
"The public sentiment towards police has been largely positive. We received a lot of support from locals for our police checkpoints and the fact that we are turning away Aucklanders who come up to stay in their baches."
Davis said while generally crime rates were down, police increasingly received reports of family violence.
"It's not likely that we'll go back to normal for some time – even if we go to alert level 3. Help us to get over this hump. Stay calm, be kind, keep yourself and others safe."
Northland Police overall were happy with the behaviour of drivers over the Easter weekend and in the lead-up period.
Sergeant Terry Phillips says Police conducted checkpoints on State Highway 1 at Uretiti on Wednesday, Thursday and Friday and there was minimal traffic.
"The majority of people had a good reason for being out on the road when we spoke to them. There were a number of people who unfortunately were out driving when they shouldn't be. This included people driving up from Auckland over the long weekend and other people who were driving to the beach for a swim or surf.
"These people were given warnings and educated around the alert level 4 restrictions and some of them were made to return home."
Phillips says about 35 motorists were given warnings at the checkpoint over the course of three days.