"It is only a matter of time before Northland has a positive Covid-19 case and it is imperative that everyone who can is vaccinated against Covid-19 as soon as possible," chief executive Dr Nick Chamberlain said.
"Even if it doesn't turn out to be positive, this would be the second near-miss in the last week after a case last week in the Far North that turned out not to be infectious while up here.
"We've seen in nearly every other country in the world what happens when the virus rolls through a community of unvaccinated people, and it's grim."
Whangārei Mayor Sheryl Mai reminded people that the person was from Auckland, however, "we have to take this seriously".
She reiterated Chamberlain's message saying it was important that everyone got vaccinated.
"While we are waiting with bated breath for further results this is a reminder to us that nowhere in New Zealand is safe if we're not vaccinated."
Mai said people should listen to advice from health officials at this time.
Of the 164,526 eligible Northlanders, there are still 60,000 people to be vaccinated.
Recent scientific modelling gave a grim outline of how things might look with various vaccination coverage levels, the DHB said.
If 70 per cent of Northland's population were vaccinated, 60,000 to 80,000 Northlanders would become infected with Covid-19 over two years.
In addition, over 100 Northlanders - likely the most at-risk who are older or have underlying health conditions - could die.
Hospitalisations would peak at 200, putting considerable strain on our health system.
The wait for Northlanders to access healthcare such as hip replacements, cataract surgeries and some cancer treatments would be prolonged.
At 90 per cent, the number of people affected significantly reduced. There would still be an impact that must carefully managed, the DHB said.
Around 4000 Northlanders would be infected with Covid-19, two people at any one time would be hospitalised, and approximately ten people would lose their lives to the virus.
"Vaccination is our best protection against Covid-19. You can't keep relying on lockdowns and staying in our communities hoping it won't affect you, because it will find you," Dr Chamberlain explained.
"Remember, the Covid-19 delta virus is seeking out unvaccinated people who have no resistance to it. The higher our vaccination rates, the fewer restrictions we'll need to keep the virus under control."
Covid-19 vaccination clinics are available throughout Northland, at general practice, pharmacy, Māori health providers and DHB clinics.
"I can't stress enough how important it is for our whole community that as many of us are vaccinated as possible," Chamberlain said.