A sustained and traumatic attack by two dogs that mauled several sheep to death as others fled into a swollen river and drowned, has cost a farmer and the dog owner dearly.

The situation was made worse by a subsequent attack on the dog control officer investigating what was described in court today as a grim attack on the animals which would have suffered "horrific deaths".

Dog owner Mark Gilovitch had earlier admitted four charges of being the owner of a dog that attacked a person and that attacked stock.

The charges related to the deaths of 40 sheep, although Gilovitch claimed in court today the total was 37. Of those, 17 were killed in the attack, either outright or as a result of their injuries which meant they had to be euthanised.

The 20 unaccounted for fled into the river and drowned, although a further few had managed to reach an island and were saved.

Up to 20 sheep were drowned in the Motueka River after fleeing a prolonged attack by two dogs. Photo / Tracy Neal

Judge Tony Zohrab told Gilovitch during sentencing in the Nelson District Court today that the summary of facts made grim reading.

The attack happened on a property in the Motueka Valley, where the complainants operate a family-run sheep farm and grazed their stock, on July 16 and 17 this year.

On this occasion, they had a flock of 250 sheep grazing in an orchard on the boundary of the Gilovitch's property.

His dogs were Kuti - a female Border Collie, Black and Blaze, each a male Whippet cross, and Puc, a male Border Collie cross.

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On the evening of July 16, a neighbour saw two dogs chasing sheep; one appeared to be a Border Collie and the other was described as a black dog.

The dogs had singled out one animal and had caught it.

The neighbour intervened and the dogs ran away but she saw the sheep had its throat torn, its leg was injured and it couldn't move.

The neighbour alerted the sheep owners who arrived the next morning and found a large number of sheep had been killed, injured or were missing.

He and an employee at the orchard where the attack happened then called the dog control officer, John Griffiths, who arrived soon after.

He knew Gilovitch on the nearby property owned a number of dogs, and that they matched the description of those involved in the attack.

As he approached his property, Gilovitch opened the kennel and released the dogs to Griffiths who had said he planned to seize them.

The dog named Kuti, which had not been involved in the attack on the sheep ran up to Griffiths and bit him.

A dog control officer investigating the mauling of a flock of sheep in the Motueka Valley was then attacked by two dogs, one of which was a Border Collie. Photo / 123RF

Blaze, who had also been released then followed Kuti, and also bit Griffiths - a former police officer who has been a dog control officer in the Tasman District for more than four years.

He told Open Justice that the attack was completely unexpected.

"Two of the dogs came up to me and I thought they were just coming up to sniff me and without warning or provocation two dogs attacked me."

Griffiths was bitten on the hip and leg in the attack which drew blood and left him needing medical attention.

He said while they were not particularly serious injuries, the incident was alarming.

"After something like this you do second-guess yourself.

"I thought, 'did I do everything right, did I contribute to what happened', but with a body camera I was able to review it and from that, I was able to realise there was nothing I could have done to prevent what happened."

Griffiths said he was trained in knowing how to react, and just stood still, but they went "straight in".

"Their blood was up, and once they get into that pack mentality … I was perhaps lucky the owner was there. If he hadn't been the attack might have continued."

He managed to kick the dogs away as Gilovitch called them off, returned them to their cages and apologised to Griffiths.

As he placed two of the dogs in his truck Gilovitch was told Kuti would also have to be seized as she was responsible for the attack on him.

Gilovitch was reluctant to release her and blamed Griffiths for causing the attack, claiming the dogs were aggravated by him driving up to the property.

Two of the dogs were euthanised, and Gilovitch later euthanised Kuti himself.

The Tasman District Council prosecuted Gilovitch, who pleaded guilty by notice last month.

The council's regulatory manager Adrian Humphries told Open Justice it was "extremely rare" to see someone in the team bitten.

The council's lawyer Antoinette Besier told the court last month that Gilovitch had paid the owners of the sheep $4000 towards the loss valued at $7000.

She told the court at today's sentencing that the offending was "quite polarised" with respect to culpability.

Besier said Gilovitch's actions had been "extremely irresponsible and reckless", including that he had tried to blame the dog control officer for what had happened to him.

He had also tried to blame the owner of the sheep for grazing stock so close to his property, knowing there were dogs on it.

"This was particularly serious.

"Two dogs operating as a pack hunted for a sustained period. Those sheep would have suffered horrific deaths."

Besier said in Gilovitch's favour, he had stepped up and had met with the owner of the sheep who had shown him photographs of the injured animals.

"He apologised and was extremely remorseful."

A spokesperson for the family which owned the sheep told Open Justice they were satisfied with the steps taken so far, and that Gilovitch had been remorseful.

"He had been upfront about helping to pay for the damage.

"He's been really easy to deal with compared with others who in the past haven't owned up to anything.

"He knows it's not a nice thing to happen and we're thankful for all he's doing to try and help."

Gilovitch, who was in court today, said it was the first time his dogs had ever attacked a person, and he was left shattered by what had happened.

"It was not intentional - they have never attacked anyone like that before."

Gilovitch reiterated that he thought it unwise for someone to place sheep so close to his dog kennels, and that he perhaps should have been told beforehand this was happening.

Judge Zohrab said people were allowed to do what they wanted on their land while others were also expected to look after their dogs.

"In a rural area you can't have dogs wandering around and that's where the fault lies," Judge Zohrab said.

He said the attack on the dog control officer was carelessness on the part of Gilovitch, and that it was lucky it was not more serious, although the mental impact could not be ignored.

He said while fining Gilovitch $1040 for charges in relation to the attack on Griffiths and $840 for the attack on the stock, that while he had initially been irresponsible he had then acted appropriately.

According to the Tasman dog control activity report for 2021-22 there were 21 complaints received about dogs attacking stock and 46 complaints about dogs attacking people.