At least four fires in bush and grassland near Lake Waikaremoana in the last six weeks are being treated as possible arson.
The latest was on Tuesday and kept Tuai fire volunteers, DoC crews and a helicopter busy for several hours, although the site near Tuai School was still being monitored regularly yesterday.
Rural fire officer Rob Sheeley was notified of the fire about 10.20am on Tuesday, and crews were involved up to about 7.30pm.
Mr Sheeley said aerial photos highlighted the extent of the problem and an investigator was called in to try to establish how the latest fire started.
It came to within 50 metres of the school, which is closed for the summer holidays, but he said it could have been more serious. The fires were being treated as possible arson, or extreme carelessness, but Mr Sheeley said whatever happened whoever was responsible should not have been on the land.
The fire danger in the area had been low but had been drying rapidly, which has led to restricted fire seasons being put in place across Hawke's Bay, meaning no fires in the open can be started without a permit being granted.
But Hawke's Bay can expect to wait a while yet before hitting the 30C-plus highs of the past, according to MetService forecasts.
Urban temperatures over the next week in the region, and throughout the east coast from East Cape to Wairarapa, are expected to peak about 28C on Sunday, while the highest national temperatures over the next week are expected to be about 30C in Central Otago on Friday and Saturday.
With no rain, soaring temperatures and tinder dry grass, now isn't the time to be burning rubbish, Paddy Driver, the Tararua's principal rural fire officer warns.
"The fire danger is bordering on very high and anyone planning on burning rubbish should wait until there's more moisture around," he said.
"There's a big danger now with a lot of long grass around and if you light a fire and it gets away on you, you'll be liable for the costs. It would be an idiot who would consider lighting a fire out there at the moment."
Mr Driver said the fire which destroyed a woolshed on Top Grass Rd on Monday afternoon was the result of a rubbish fire not far from the shed.
"A little strip of dry grass smouldered away and the result was the woolshed burning to the ground," he said.
"Although much of the long grass in our rural areas looks green on top, there's about eight inches of dead stuff below and a fire can smoulder away for a long time in this.
"Now isn't the time to burn off rubbish, wait until autumn."
After weeks with no rain and temperatures in the high 20s, Mr Driver said he's planning to put fire restrictions in place on Monday. "That will mean people won't be able to light fires without a permit, but in the meantime, if rural residents want advice or information they can ring the council on 06 374-4080," he said.
Additional reporting byChristine McKay