"Seventy-four close contacts have been identified following the confirmed case of a student at Taradale High School with Covid 19. All those involved are following public health advice," a Hawke's Bay District Health Board spokeswoman said.
Those close contacts must self-isolate for 10 days which includes a group of students at the school.
Hawke's Bay recorded seven new cases on Saturday and eight new cases on Sunday.
Meanwhile, New Zealand recorded a staggering 810 new Covid cases on Sunday across the country, 623 of which were in Auckland.
The Ministry of Health expects cases to continue to rise.
"The sharp increase in new cases today is another reminder that, as expected, the highly transmissible Omicron variant is now spreading in our communities as we have seen in other countries," a Ministry of Health statement said on Sunday.
"Our expectation is that cases will continue to increase over the coming weeks and we're asking people to do all they can to slow the spread of the virus and protect themselves and their whānau."
Taradale High School posted on social media letting parents know a group of students would be self isolating for 10 days, and gave advice about other household members.
"A group of students have been identified as close contacts of a student who tested positive for Covid 19," the message read, which was also emailed out to parents.
"These students are isolating at home for 10 days and will be tested as per Ministry of Health and Ministry of Education protocols.
"During this period students will be receiving phone calls from the National Investigation and Tracing Centre."
Citing advice from Hawke's Bay DHB, the post stated that members of a household who lived with any of the close contacts would not be required to self isolate, unless they developed symptoms.
The self-isolation period for close contacts is 10 days from last exposure with Covid tests required immediately and on day five and eight, according to the Ministry of Health.
The Hawke's Bay District Health Board also confirmed there had not been any further cases at Te Mata Primary School in Havelock North, where four pupils tested positive at the start of last week.