Fire crews from Balclutha and Milton responded to the callout about 9.30am and had the blaze under control in about 15 minutes - but Milton Deputy Fire Chief Robbie Philip said the incident served as a warning to all farmers who had controlled burns on their properties.
The flare-up, on a Moneymore farm, was first seen by Otago Daily Times photographer Stephen Jaquiery, who raised the alarm with the landowners.
Farmer Scott Johnstone used a digger to try to contain the fire but the flames soon engulfed a derelict shed and began crossing State Highway 1, forcing police and fire crews to temporarily close the road.
Mr Johnstone said the burn-off was lit more than six months ago and had been smouldering away with no trouble.
It had slowly spread and some fickle winds in the morning may have contributed to the fire igniting some nearby bush and scrub.
The large trees alongside the highway were due to be removed soon but Mr Johnstone said he would have preferred if the blaze had started further off the road.
Damage to the property was superficial, he said.
Mr Philip said the incident highlighted how important it was for farmers to ensure burn-offs were controlled.
Two appliances and a rural fire tanker attended and the fire took 15 minutes to control.
North and southbound traffic was diverted through Moneymore briefly while fire crews worked to control the blaze and then dampen down hotspots.
Mr Philip said many people did not realise how dry it had become in recent weeks and urged farmers to ensure firebreaks were in place.
"People need to keep a good eye on burn-offs so we don't get any more trouble."
•Strong winds blew down power poles and electricity lines in Central Otago yesterday, sparking two vegetation fires near Alexandra.
The Alexandra Volunteer Fire Brigade was called to a tussock fire near Fruitlands just before midday.
It took more than an hour to put out the fire, which had started with a power line breaking from a pole and setting alight grass underneath.
Senior Station Officer Glen Gray said about 200sq m of grass was burnt.
Nothing else was damaged.
A second callout came at 2pm, when the brigade attended another vegetation fire near Springvale.
Mr Gray said the minor fire started when a power pole fell over.
It took the brigade about 40 minutes to dampen the fire.
Power lines in other parts of the district were also affected by wind.
Delta Central system control manager Graeme Johnson said power was briefly cut to parts of St Bathans and Becks after a wire was broken by wind.
Power was also cut to Springvale and Chatto Creek customers for part of the afternoon after a power pole between Alexandra and Omakau broke.
