Tradies and farm workers frantically baled buckets of grain in a desperate attempt to free an electrical contractor entombed in a grain silo on a Southland farm today.

Riversdale Volunteer Fire Brigade chief fire officer David Stevenson praised the quick work of a number of contractors, builders and farmers who climbed into the massive silo and saved the life of the local Riversdale man.

Mr Stevenson said it was thanks to their quick thinking and immediate action that the man survived.

"He was lucky because there were builders, two or three farmers and another electrician there.


"The grain covered his head. Those guys did a fantastic job. They got him to a point of breathing.

"That's the only reason he survived, really."

Mr Stevenson said he arrived at Nine Mile Rd rural property just before 10am, fearing the worst to find "a whole lot of people" inside the 9m silo trying to get the trapped man out.

"He was submerged - but I can't tell you for how long - and they dug him out. My firefighters secured him and then the other firefighters dug him out once we had a decent amount of them there."

He said the man was given oxygen while others in the rescue effort used buckets to clear the grain from around him.

Mr Stevenson said the trapped man was conscious but not very coherent.

Once freed he was put in a harness and helped out of the farm building by firefighters and able to climb gingerly down the roughly three-storey extendable ladder.

Mr Stevenson said the contractor was standing in the silo doing wiring when the accident happened.

However, he did not know what happened inside the grain storage building and said it was a matter for authorities to find out.

"I'm not really sure exactly what happened - we don't really know why he went down there in the start - that's under investigation," Mr Stevenson said.

The man in his 60s was in a serious condition and was flown to Dunedin Hospital by the Otago Rescue Helicopter.

Four people who had been inside the silo, including two firefighters, were taken to Gore Hospital after concerns about the amount of dust they had inhaled.

St John southern spokesman Ian Henderson said the four people taken to hospital had a range of minor to moderate conditions.

Another four people who were inside the dusty silo were assessed at the scene by paramedics and required no further treatment.