A firefighter has suffered steam burns trying to extinguish a major fire which gutted the Four Square premises in Waipawa.
The firefighter was transferred to Hawke's Bay Hospital in a moderate condition, confirmed a fire and emergency services spokeswoman.
Another person was treated at the scene of the fire, which is not being treated as suspicious.
Waipawa Four Square was ravaged in a fire "well ablaze" by the time Fire and Emergency services responded to it at 4.29am on Sunday.
The fire, which impacted adjoining premises Lulu and Max daycare as well, was fully extinguished by 7.47am.
There were eight fire tankers, three support vehicles, and four tankers to supplement the town's water supply team, which helped extinguish the supermarket fire.
Central Hawke's Bay District Council mayor Alex Walker said the supermarket was at "the heart of the community", and the fire had left everyone "devastated".
"We are a strong community, and right now our first priority is to support Graham and Rachel and the wider Four Square team and Lulu and Max families through this tragic time," she said.
"They have had a devastating loss with the fire, their jobs, the security and what being part of the Four Square family meant to them, they are forefront in our minds.
"My thanks to Fire Emergency New Zealand, police, council and council contractors who have gone above and beyond.
"We are already working closely with our Ministry of Social Development partners to understand what wider considerations and impacts may also arise for the wider community."
A spokeswoman for Lulu and Max said they were overwhelmed with the community support.
"The community support has been amazing, and we are just figuring out what our next steps would be," she said.
"We will operate our before and after school care out of Waipawa Primary School hall tomorrow."
Walker said the daycare was one of three businesses, in the same building which housed Four Square.
"There is smoke and water damage in Lulu and Max," she said.
"The front part of the building had damage to it as well."
Owner of the building Jason Wray said, "We are 100 per cent behind supporting the CHB community through this tragedy and our intention is to rebuild as soon as we can."
With such extensive damage, a local business is stepping in to help those impacted.
In light of the fire, Waipawa Butchery owner Duncan Smith said the butchery would be delivering to the elderly for free starting Monday, for as long as required.
"There are lots of elderly living around here and they would struggle without the supermarket, we didn't want them panicking," Smith said.
"We are set to roll with our van and mobile eftpos machines, so they don't have to pay online.
"The supermarket fire is a big deal around here. It's been burnt to the ground pretty much, only parts of the structure are still standing.
"It's a definitely a blow to the elderly and we will look after them the best we can."
Waipawa resident and CHB Museum staff member Rose Chapman said she sends her sincere sympathy to the owner of Four Square and all the "lovely people who work there".
"We love that shop and hope they can soon rise again from the ashes," Chapman said
The fire closed off State Highway 2 until noon on Monday, and Walker said it was reopened with speed restrictions in place.
"It's a 30km zone in front of the building on State Highway 2," she said.
"It's restricted through the main street, past the building."
The fire is being investigated by specialist fire and emergency investigators and the cause is, as yet, unknown.