"It is more about staffing than children. I have to have teachers for students."
She said it was extremely difficult to get relievers at the moment and made sense to switch to online learning.
"It is a combination of Covid, the flu and general unwellness and viral things that have been hitting kids and staff, but we think the flu is the main [illness]."
She said they were catering for children of essential workers at the school, such as medical workers, and had about six or seven at the school on Tuesday.
"[Essential workers] just need to ring the office and make arrangements with us and we will organise something here at school for their children."
Gray, who is retiring as principal at the end of this year, said this was the first time the school had to close its physical classes this year.
It is not the first school to be closed due to illness this year in Hawke's Bay.
Taradale High School closed in February and switched to online learning due to an outbreak of Covid.
24 people in hospital with flu
There are currently 24 people in Hawke's Bay Hospital battling serious cases of influenza (the flu).
Hawke's Bay DHB medical officer of health Dr Nick Jones said it was important to get your flu jab.
"The flu jab is available now at your GP, pharmacy or hauora provider and is free for pregnant women, Māori and Pasifika people aged 55 and over, everyone 65 and over and people with long-term medical conditions and children who have been in hospital with respiratory illness such as asthma," he said.
"It is especially important that pregnant women and those with underlying health conditions get their free flu jab as they are more likely to become seriously ill from influenza."
Nationally there were 6133 community cases, 377 hospitalisations, 7 in ICU and 23 deaths.
Of the deaths, one person was from Northland, five were from the Auckland region, three from Waikato, one from the Lakes DHB region, four from Taranaki, two from MidCentral, one from Hawke's Bay and two from the Wellington region, one from South Canterbury and three from Southern.
One person was in their 50s, three were in their 70s, 11 were in their 80s and eight were aged over 90. Of these people, 15 were women and eight were men.