Lightning strike claims cows (warning graphic image).

Alan Wills is grateful no staff were in the paddock when lightning stuck, killing eight of his young milking cows.

The Reporoa dairy farmer said he was out of town last Thursday, when a storm struck bringing more than 54mm of rainfall to the region and dozens of lightning strikes hitting the immediate area about 3pm, killing the eight 2 to 3-year-olds as they waited to be brought in for milking.

The Wills have a herd of 500 milking cows, which are housed in three separate herds on their Forest Rd farm.

While they had lost eight "good" young producing cows worth about $2000 each, nobody was injured or killed in the unfortunate incident, Mr Wills said.

Staff found the dead cows when they went to collect them for afternoon milking.

The cows are pictured in a row beneath a line of trees bordering a fence.

"We are eternally grateful we didn't have anyone in the paddock. Had the storm been 10 minutes later or the milking a bit quicker we would have had a man in the paddock. We were so fortunate. This type of thing happens from time to time, though. One guy in Taranaki lost 120 cows last week because of poisoning. These things happen."

Staff were already concerned and had brought the two previous herds in by ute, rather than bike, because of the rain and lightning, he said.

Ringing to see how things were while he was away, Mr Wills said his manager Jason Withers informed him long-awaited rain was drenching the farm and that the cows had been killed.

"We've lost half a season's production from them. It's just one of those things that turn up from time to time but at least none of the staff were hurt or killed."

The storm caused havoc across the region, uprooting trees, flooding roads and leaving many paddocks looking like lakes - some looked like fast-flowing rivers. One Rotorua farmer was left with a 300m driveway looking like the Grand Canyon with huge holes the entire length, others wading through rising waterways.

When it hit the region, farmers were praying for rain after experiencing the driest November on record. Only 14mm of rainfall was recorded in Reporoa during November, 100mm less than normal.

Waikite Valley diary farmer Ches Chesby lost power to his shed during afternoon milking last Thursday, when lightning struck a power pole outside the property he farms, forcing he and his staff to milk by generator.

They didn't finish milking until after 10pm.

"It was pretty bad," he said.

More than 700 lightning counts were recorded in Reporoa last Thursday afternoon.

MetService weather forecaster Heath Gullery said this was a relatively high count for the region.

"It's not a big area, so it's quite a bit to have 700," he said.