* Nationwide lockdown will be extended until at least next Tuesday
* Covid-19 has been detected in Wellington, with three confirmed cases
* Johnsonville Countdown and pharmacy, Porirua Sushi outlet among more than 200 locations of interest
* A bar worker at a Mitre 10 awards has tested positive and up to 1000 people may be close contacts
* 31 cases, 11 new cases announced on Friday
Nearly 7000 secondary school students across Auckland are considered close contacts of teenagers who have tested positive for Covid during the Delta outbreak.
All students and staff at De la Salle College, McAuley High School, Avondale College, Northcote College and Lynfield College have been told to get tested and isolate for 14 days as they may have caught the potentially deadly virus from students who were already infected.
McAuley, in Ōtāhuhu, has a roll of close to 800 and the student attended class while infectious on August 17.
De la Salle, in Māngere East, has a roll of close to 1000. One of its students also attended the school on August 17 while infectious.
De La Salle principal Myles Hogarty said there had been a fair amount of fear and uncertainty among families since a case was detected at the school as 87 per cent of students were Pacific and at high risk.
"We are all aware this Delta strain is moving very very rapidly."
Hogarty said he was told a student had tested positive at about 6pm on Friday night, just hours after staff had met to take a breath and say "so far so good".
"It all changes, of course, very quickly ... all of a sudden we have several thousand people being forced to go in and get tested," he said.
"Our priority was to give our community very clear and precise communication, and urge them to follow Ministry of Health guidelines," Hogarty said.
He said while parents had been responding positively, and were grateful for the clear and direct communication, there was some frustration with wait times.
"I've spoken with the Ministry of Health and offered the school grounds as a testing site but their response is that they are facing huge struggles just to staff the current ones," Hogarty said.
Avondale, in central Auckland, has a roll of nearly 3000. On Wednesday August 18, it was announced a 25-year-old female teacher at the school was among the first known community cases of the virus.
On Thursday, director general of health Dr Ashley Bloomfield revealed that five more people linked to the school had tested positive.
Yesterday, Avondale College posted a message from Auckland Regional Public Health Service (ARPHS) encouraging those who had not been tested to make sure they did so over the weekend.
"We realise that testing has been difficult and we thank you for your patience and understanding," the notice said.
More than 1000 students are enrolled at Northcote, in North Shore, and one student was confirmed to have Covid. The student was infectious when at school on the Monday and Tuesday, August 16 and 17.
Lynfield College, in Mount Roskill, has a roll of nearly 2000. A student of the college tested positive for the virus and was considered infectious when at the school on Monday and Tuesday, August 16 and 17.
Lynfield College principal Cath Knell said many in the school community were "finding it challenging" to get a Covid test after a student tested positive for the virus.
Family members of our students and staff need to self-isolate until a clear 5 day test result has been returned, she said.
"Everyone who was on our college grounds on Monday 16th and Tuesday 17th August needs to be tested and self-isolate for 14 days".
Knell said she had requested the school be used as a pop-up testing site but she had yet to hear from health officials about whether this was possible.
"We are mindful of the immense workload currently faced by the health system and appreciate their support of our college and our community.
"We understand that it's a very worrying time but are thankful that our school community is characterised by manaakitanga and care for one another.
"We know that the virus is the problem, not the people. The way forward is for us to continue to work as a community, to follow the public health guidelines for alert level 4 and to support each other," Knell said in a letter to parents.