At a press conference at 2pm, Nelson-Marlborough DHB chief medical officer Dr Nick Baker said exactly how the two clusters are linked is yet to be determined.
"The next three or four days will help to know how far it has spread.
"Covid is here, we can expect case numbers to increase. This is something we've been planning for, its now time to activate our plans," he said.
Baker said no cases have yet to require hospital-level care.
"I don't think we should be too despondent, it's not uncommon to get these sorts of numbers.
"It does indicate spread before people knew they had covid but now people will know and have a test earlier."
Wastewater in the region is being tested but the frequency is unknown, Baker said.
"We had no warning from these tests."
It comes after it was revealed two staff members had tested positive for the virus at two schools in Nelson.
Enner Glynn School and Broadgreen Intermediate have temporarily closed while a risk assessment is undertaken.
Baker said they are still working through who is a close contact and who is a distant contact at the schools.
Four new locations of interest in Nelson were added to the ministry's website yesterday afternoon.
"People in the Nelson-Tasman region are asked to check this page as it is updated regularly."
The Nelson-Marlborough DHB has a full vaccination rate of 85 per cent, with 92 per cent having had one dose.
Testing is available in Nelson-Tasman today at:
• Saxton Field parking area, Suffolk Rd, Stoke from 9am to 8pm
• Trafalgar Centre carpark, Paru Paru Rd, Nelson from 9am to 2pm
• Richmond Showgrounds, 359 Lower Queen St, Richmond from 9am to 8pm
• Motueka Recreation Centre: Old Wharf Rd, Motueka from 9am to 5pm
