The Ministry of Health has released a number of locations of interest in Nelson, including a restaurant and shopping mall.
There is one confirmed case of Covid-19 in the Nelson-Tasman region.
The Ministry of Health announced the case at 1pm. The positive test result was returned on Sunday night.
The case and their close contacts are in isolation, with testing of those contacts underway, a ministry spokesperson said.
"Investigations into the possible source of infection are ongoing.
The Nelson Lone Star was visited on Friday November 19 between 8.15pm and 8.45pm.
That same day The Richmond Liquid Laundromat was visited between 4.45pm and 6.30pm.
Z Rutherford Service Station was also visited that day between 8.30pm and 9pm.
Anyone at these locations during this time must self-monitor for Covid-19 symptoms for 10 days after you were exposed at this location of interest.
• Richmond Liquid Laundromat, Friday November 19 between 4.45pm and 6.30pm
• Lone Star Nelson, Friday November 19 between 8.15pm and 8.45pm
• Z Rutherford Service Station, Friday November 19 between 8.30pm and 9pm
• Z Rutherford Service Station, Saturday November 20 between 5am and 5.30am
• McDonald's Nelson, Saturday November 20 between 5am and 5.30am
• Four Square Mapua, Saturday November 20 between 4pm and 5pm
• Richmond Liquid Laundromat, Thursday November 25 between 6.15pm and 8pm
• Ewing Poultry Hope, Saturday November 27 between 10.30am and 11am
• Z Richmond Service Station, Saturday November 27 between 10.45am and 11.10am
• Richmond Mall, Saturday November 27 between 1.30pm and 2.40pm
• PAK n SAVE Richmond Mall, Saturday November 27 between 1.40pm and 2.15pm
• Hey Sushi Richmond Mall Food Court, Saturday November 27 between 2.15pm and 2.30pm
• Z Richmond Service Station, Saturday November 27 between 2.35pm and 2.45pm
It is the first confirmed case, likely to be infectious, in the region since last year.
Nelson Mayor Rachel Reese said she is sure this will be a wake-up call for people in the area.
"We've known that it will be a matter of when, not if, and as we've watched cases appear in other parts of New Zealand. We've always known that at some point this region would see another case.
"I want to encourage people to remember the good protocols we have around masks and scanning. And if you haven't been vaccinated yet, now is definitely the time to get in and get that started," she said.
When asked exactly where in the region the case is, Reese said the ministry is working through a risk assessment and no further details on the case will be provided until then.
As of Saturday, 91 per cent of the Nelson Marlborough DHB had one dose of the vaccine and 83.7 per cent were fully vaccinated.
Reece said the vaccination rate in Nelson is solid but could be better.
"I think we should see 90 per cent as not a target but if we can get beyond that, we start to reduce the risk to our whole community. We've still got room to improve."
Several exposure events are being assessed and any locations of interest confirmed will be published on the Ministry's website.
Meanwhile, five close contacts of a border case announced in Christchurch yesterday are now self-isolating, with testing under way.
The case travelled from Auckland to Christchurch on November 25 on Air NZ Flight NZ8475.
"Anyone who is considered a potential contact of this case will be contacted directly. Unless you are contacted, you are asked to monitor for symptoms, and get tested straight away if you develop any consistent with Covid-19."
People living in Canterbury are also asked to monitor the ministry's locations of interest website.
"Every new case is an urgent reminder to get tested if you're feeling unwell. Testing at high numbers will help to minimise and contain the spread of Covid-19 in Canterbury."
AA and National Road Carriers warn of severe disruption to freight and transport.