South Taranaki mayor Phil Nixon confirmed 11 cases are linked to the school, with no adults yet infected.
"There's a big feeling of apprehension around the town at the moment. We're in orange, but people have started to social distance and take their own precautions. People are pretty worried," Nixon said.
His understanding was the original Eltham case announced over the weekend had still not been linked to any other case either in Taranaki or elsewhere in the country.
Eltham Primary School, which has a roll of about 150 students, is now closed for the remainder of the year. Yesterday was the school's final day, with students coming together for a Christmas performance, posted to the school's social media pages.
Steffy Mackay, an Eltham-based South Taranaki district councillor, said she had been informed of 11 cases at one school in South Taranaki, with a number of probable cases also in the community.
There is also a new case of Covid-19 in Hāwera, about 20 minutes south of Eltham.
That case is believed to be connected to the Eltham outbreak.
On Wednesday, the Ministry of Health released locations of interest in Hāwera:
• Z Service Station Hāwera, 226 South Rd - Thursday, December 9, 7.12am-7.17am - Thursday, December 9, 10.16am-10.21am - Friday, December 10, 7.25am-7.30am - Friday, December 10,10.25am-10.30am
• Bunnings Hāwera, 175-179 Glover Rd - Thursday, December 9, 3.22pm-3.52pm - Friday, December 10, 11.05am-11.35am
• Unkas Jewellers Hāwera, 189 High St - Friday December 10, 4.36pm-4.46pm
• Pak'nSave Hāwera, 54 Princes St - Friday, December 10, 4.30pm-5.30pm
• Pizza Hut Hāwera, 220 High St - Saturday December 11, 5.00pm-5.20pm
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.
Māori Party co-leader Debbie Ngarewa-Packer said Ngāti Ruanui and Ngaruahine had completed around 200 saliva tests since standing up testing in Eltham and Hāwera early this morning.
Ngarewa-Packer, who is today absent from Parliament and in Eltham leading the testing response, said she understood case numbers today had ballooned from the 11 initially reported.
"We are above 20 confirmed and probable cases now. I don't think we will be seeing the back of this for some time to come," she said.
The initial 11 cases from Eltham Primary School were detected via saliva testing, operated by the two iwi in the town on Sunday.
Ngarewa-Packer said chances were a number of the cases wouldn't have been identified if saliva testing wasn't readily available.
"These kids don't like the idea of a big stick up their nose. Saliva testing probably really helped getting them out here."
Ngarewa-Packer said she had today spoken to a number of the families affected by the outbreak in Eltham, many of whom were shocked and confused.
"These whānau are going to be in isolation for Christmas. They don't know what happens with work, with whānau and some of them only have one person in the house with Covid - they don't know if they'll get it too, or may even already have it."
"It's a scary time for a lot of whānau here, but the community is wrapping around them."
Teams are now travelling to residents' homes to conduct testing, due to them either being a close contact or having someone with Covid-19 already isolating at the property.