According to Willems, unvaccinated or partially vaccinated people were most at risk.
He said it was likely around 75 per cent of Northland's unvaccinated population - more than 20,000 people - will get Omicron.
The Northland cases are out of 209 community cases reported across the country today.
Further to today's cases, positive wastewater results were detected in Whatuwhiwhi - a settlement at the northern end of Tokerau Beach on the Karikari Peninsula - on January 31.
The DHB noted Covid testing was available in Kaitāia at 11 Matthews Ave.
Positive wastewater was also detected in Mangawhai on February 1.
The district health board announced Coast to Coast Healthcare were providing routine drive through Covid testing seven days a week at 77 Morrison Drive in Warkworth or Monday to Friday at 72 School Road Wellsford
Willems said a "slower and more controlled outbreak" will "help protect Māori and our most vulnerable" by providing more time for vaccine uptake as well as support "the healthcare system to care for everyone who needs it safely".
"In an extremely fast and uncontrolled outbreak, Northland is more vulnerable to the risk of health services and critical services being unable to keep up with demands."
He said for most people the severity of the Covid virus was likely to be milder with Omicron "but many will still have severe disease needing hospital care".
"Because of the infectiousness and speed of spread of Omicron, the numbers of people with severe disease at any one time could still pose a risk to the health system and critical services.
"We'd like to make sure that everyone who needs hospital care will be able to access it," Willems said.
He noted the number of people needing to isolate and stay at home at a single time could mean fewer people were available to keep critical services operational.
"Willems stressed how vaccination remained "our most effective weapon against the virus".
"However, now that Omicron is in our community, we expect case numbers to grow rapidly and put our Northland health system other critical services like food, water and energy providers under considerable pressure."
The Ministry of Health reminded Kiwis that one of the best things they can do is to get their booster as soon as it is due. From today, 1 million people are now eligible for their booster after the interval was reduced from four to three months.
They said boosters lowered your chances of getting very sick and being hospitalised. Being boosted also helps slow the spread of the virus. If you're over 18 and your booster is due, please get it now.
Only those who have Covid-19 symptoms – or have been at a location of interest at the relevant time – need to get a test and isolate at home until a negative result is returned, the ministry said.
The most common early symptoms of the Omicron variant are a sore or scratchy throat and a runny nose. If you have any of these symptoms, please get a test.
For a list of Covid vaccination and testing stations, and opening times, go to https://www.northlanddhb.org.nz/home/covid-19/
Meanwhile, Northland is only a couple of hundred doses away from having 90 per cent of the eligible population with their first doses, as the region stands at 89.8 per cent for first doses and 87 per cent for second doses.
New locations of interest reported in Northland are:
The Rusty Tractor Café & Trading Store Kerikeri, 582 Kerikeri Rd, on Friday, January 28 from 12.09 pm - 12.50 pm; Rebel Sport Kerikeri, 96 Kerikeri Rd, on Friday, January 28 from 11.11 am - 12 pm; Briscoes Kerikeri, 96 Kerikeri Rd, Saturday, January 29, 11.15 am - 12.45 pm and New World Kerikeri, 99 Kerikeri Rd, Saturday, January 29, 12.58 pm - 1.15 pm.
If you were at any of these locations at the times identified you should: Self-monitor for Covid-19 symptoms for 10 days after you were exposed. If symptoms develop, get a test and stay at home until you get a negative test result.
How to slow down the spread of Omicron:
Prevent -
· Get vaccinated and get boosted. It's not too late.
· Strongly consider postponing or not attending larger gatherings, especially those happening indoors. Meet in smaller groups and meet outside. This is especially relevant for residents in the Kerikeri area given the situation there.
· Wear the correct mask whenever it is indicated
· Keep your distance from others as much as possible
