Whanganui firefighters are urging people not to light fires on beaches after a blaze at Ototoka Beach that spread on to the steep hillside above.
Senior station officer Bryan Coskerie said one fire truck and a tanker initially went to the fire about 4.40pm on Tuesday but eventually four crews and one rural fire crew were needed at the scene, with the Ratana Fire Brigade called in to Whanganui on standby.
"It was a fire on the beach that had spread into tussock and scrub on the hillside and it spread up the hill which was quite steep," Coskerie said.
"The fire was approximately 100m by 90m in the marram grass but it had spread to 120m by 100m by the time they got on top of it.
"It's potentially serious out there because of the type of terrain and because the marram grass burns quickly.
"We really encourage people not to burn fires on beaches. Should they have a fire on the beach, they really have to ensure they extinguish it without leaving it unattended, which is possibly what happened in this incident. It poses a risk for farmland as well as the beach vegetation."
Although fire restrictions for the district had been lifted, it was still extremely dry in some areas and, depending on the type of vegetation, a fire could spread quickly, Coskerie said.
"A fire can double in size in three minutes," he said.
"It puts a lot of pressure on the Fire Service to get access and equipment into some fires."
Crews were on the scene for about two hours. During that time, there were also calls to a fire alarm at The Grand Hotel and to a report of smoke in Castlecliff where someone was burning rubbish.