There have been 24 new community cases of Covid-19 reported in New Zealand today - the second daily increase in a row.
The Health Ministry said 21 of today's cases had a known connection with previous cases.
Speaking at today's government briefing, Director of Public Health Dr Caroline McElnay said health authorities did expect a number of further cases in the coming days as some of the new recent cases came from large households.
"What we know about Delta is that it's more infectious, so we do expect more household contacts to subsequently test positive, but these contacts are already in isolation."
All of today's cases were in the Auckland area and all of Wellington's 17 cases have now recovered.
There have now been 1050 total cases associated with the current community outbreak.
There were 20 community cases yesterday, 19 were household or known contacts of other cases, and only one was unlinked, the ministry said.
Eleven and 13 cases were reported on the previous two days.
There are 13 people in hospital with the coronavirus, with four in ICU or HDU.
There were no new cases in managed isolation today.
There has been a total of 3704 cases of Covid-19 in New Zealand since the pandemic started.
Mt Eden case
Speaking at today's government briefing, Director of Public Health Dr Caroline McElnay said a prisoner on remand at Mt Eden prison had now tested positive for Covid-19.
"He is understood to have been in the Firth of Thames area before he was taken into custody, this is within the Counties Manakau DHB area and is under alert level 4 restrictions. He was travelling with one other person who is now in isolation and is being tested today."
Two locations of interest have been added to the ministry's location of interest website.
Dr McElnay said four police staff were now isolating due to contact with this case. Because of alert level 4, only essential staff were on site, so just five corrections staff and six prisoners are close contacts of the man, and are isolating.
"This case, his travel companion, and contacts have been helpful and cooperative with our health authorities."
Prime Minister Jacinda Ardern acknowledged the "extraordinarily rigorous" protocols that led to the detection.
"Corrections treat - in level 3 and 4 - new incoming prisoners as they would an individual coming in at our border. They are tested at day zero, they continue to have tests through to day 12.
"They wear masks and staff wear PPE, and they work through a process to ensure that someone is Covid-free before they're integrated more fully into the prison environment.
"Off the back of that testing is how they've detected this new case. Whilst we've not formally linked the case yet, there is a tentative link, but more work is being done just to sure that."
Truck driver update
Dr McElnay said now 140 contacts, outside of the household, who were at locations of interest visited by a delivery truck driver who travelled outside Auckland before testing positive for Covid-19.
She said of those, 81 have returned negative test results.
Dr McElnay also issued a reminder today to people to stay vigilant for the less common symptoms of Covid-19, and to still make contact with Healthline or their GP immediately, even if they don't have the more common symptoms.
"Those symptoms are diarrhoea, headache, muscle aches, nausea, vomiting, chest pain, abdominal pain."