Several close contacts of the family with Covid-19 in Stratford are symptomatic and are being tested.
Six cases of Covid-19 were found in Stratford last week and the first locations of interest have been announced.
One man is in Taranaki Base Hospital in a stable condition, and two adults and three children are isolating at home while the DHB decides where best to look after them.
Taranaki DHB's medical officer of health Dr Jonathan Jarman said more cases are on the way.
"It's an evolving situation and we've been following up some close contacts who are symptomatic... there will definitely be more cases.
"All of Stratford should consider itself as a location of interest, and that if anyone has symptoms they need to get a test. We need to get onto this as quickly as possible."
The Ministry of Health says five close contacts are so far being assessed.
Jarman said the cases are from one family and had been very reluctant to get tested.
"We have been working with them over a day or so and eventually managed to persuade them to have a test."
He said the family had not been using the Covid tracer app so health workers are tracing their steps manually.
Two of them had been in Auckland at the end of October.
Jarman said the children have not been to school or preschool during their infectious period.
The first locations of interest announced are New World Supermarket in Stratford last Thursday, Mackays Unichem Pharmacy Stratford on Tuesday, Wednesday and Thursday, and Bunnings Warehouse in Hāwera also on Tuesday.
The eight iwi in Taranaki have called for the region to move to a level 3 lockdown.
Jarman said Ministry of Health officials will carry out a public health assessment this afternoon to determine whether a lockdown is needed.
"What we're finding is that things are changing so quickly, every time I open my computer there's another half a dozen emails."
Te Pāti Māori co-leader Debbie Ngarewa-Packer said in a virtual meeting this morning DHB officials said the family had been to medical centres in Stratford and Hāwera, but that those were not being announced as locations of interest as staff on duty at the time had tested negative.
"We have called for a Level 3, the iwi unanimously called for Level 3."
"When they tell me that somebody travelled to ED in Hāwera, they moved out of Stratford and were in Hāwera, so Hāwera has been at risk of exposure."
Ngarewa-Packer said the DHB should disclose which of its facilities had been visited by the sick family.
"We got off the phone call having absolutely no confidence in what the DHB are doing, we had more questions than answers."
"Did you go to garage, did you get kai, did you go to the dairy? You cannot tell me in eleven days you don't go and get kai."
It has been 12 days since wastewater was sampled from Stratford and subsequently found to contain Covid viral fragments, and samples from another four days also tested positive.
Ngāruahine and Ngāti Ruanui health workers are Covid testing in middle of the town, backed by their iwi organisations, and Taranaki DHB also has set up a testing station.
Ngarewa-Packer is working at Ngāti Ruanui's testing and vaccinations pop-up clinic and said traffic through the town is heavy.
"Fifty per cent of people in Stratford don't work in Stratford, they travel around the rest of the takiwā (region)."
Te Aorangi Dillon is coordinating Ngāruahine's response and said people shouldn't wait for an alert level change.
"Whānau please stay home if you don't need to be out travelling around at this point in time."
"Until we know where this is, we just need everybody to stay home and stay safe unless you need to come out and get tested."
She said more cases were likely given the way the virus had spread in Auckland, Northland and Waikato.
"We know how this travels, how it spreads, we know we have shift workers coming in and out of Whakaahurangi (Stratford) every single day."
Taranaki Māori vaccination rates are 72 per cent for the first dose and 54 per cent for the second, significantly behind the overall rates of 86 per cent first dose and 73 per cent second.
Stratford and the surrounding countryside have rates two to six per cent behind those overall rates.
Nearby Eltham is worse off, with 78 per cent having one jab and just 62 per cent fully vaccinated.