It was all hands on deck as every available firefighter in Whanganui was called in to the blaze which destroyed a historical two-storey building on Victoria Ave on Monday morning.
A glow could be seen in the sky as they left the Whanganui Fire Station at 2.49 am.
Eight appliances, including one from Palmerston North, were used to put the fire out.
Video: Richmond Campbell
Fire and Emergency Whanganui senior station officer Jes Sorensen said the fire was surrounded and brought under control but took a couple of hours to extinguish.
"Because the roof had collapsed it meant it was difficult to get to the fire underneath it," he said.
The fire had to be tackled aerially using a pontoon ladder.
Sorenson said the building was believed to be unoccupied at the time but was still being assessed.
Police and fire risk management we onsite this morning and it was too early to determine the cause or where it started.
Victoria Ave – Whanganui's main street – was blocked off for several hours, but has since re-opened.
The property remains cordoned off where little more than a facade remains.
A nearby resident said he and his wife were woken shortly after 3am.
"It was well alight - a big fire for sure."
The building has been unoccupied for some years and it was thought nobody was inside after the fire started.
"It certainly looks suspicious. How can a fire start if the building was empty?"