The man behind one of New Zealand's biggest ever cases of animal ill-treatment by a farmer is staring down the barrel of a prison sentence after admitting his inaction caused the death of hundreds of sheep and widespread suffering.

All of this happened because Colin Donald McConachy was too proud and ashamed to ask for help. Thousands of animals suffered as he sat on his hands.

The 72-year-old Marton man could be

banned for the rest of his life from having authority over farm animals, after pleading guilty in the town's district court on Wednesday to eight charges relating to ill-treatment of animals on his farms.

The Ministry of Primary Industries is hoping for the ban to be applied when McConachy is sentenced in October, where he faces a maximum punishment of five years' jail and a $100,000 fine.

The summary of facts paints a picture of McConachy as a man who, by his own admission, was "too proud and ashamed" to get help when it was offered - and needed the most.

In total, 3630 animals suffered to varying degrees because of McConachy's inaction.

An anonymous tip-off in September 2015 to the ministry's animal welfare hotline led inspectors to their horrific discovery.

They found 10 dead animals within 100 metres of entering the property. As they looked further, the death toll quickly rose.

Thirty dead sheep and two dead cows were found near a 120-strong mob of year-old cattle, which were in poor condition, ataxic and in a paddock with insufficient pasture.

McConachy then arrived, telling an inspector he had already buried about 50 dead sheep and that the rest of the 260-hectare home farm would be in a similar state.

Gates had been opened to allow hoggets and ewes to mix - something a vet quoted in the summary of facts said was against good practice - and the only feed of significance on the property was 10 hectares of kale, fenced off to all stock apart from a small number of shorn lambs.

Piles of dead sheep were found around his farm in locations away from public view, which the summary said showed he knew about the situation for some time.

Inspectors found 382 dead sheep on McConachy's farmland, while another 334 were in such poor condition that they had to be put down. Post mortems found no evidence of disease, putting starvation as the sole cause of death.

All the while, McConachy was found to have a large store of hay that, for whatever reason, he had not given to his stock.

Of the remaining 2783 live sheep, 85 per cent were in extremely poor condition.

McConachy was ordered to kill any animals that were subsequently unable to be raised.

But a visit a week after the first inspection, an inspector found seven hoggets shut in an old stock crate with no food or water. Four of the hoggets were dead, while the other three needed to be killed.

McConachy said he had put them in the crate after they went down two days prior, but forgot about them.

A vet quoted in the summary of facts said the situation highlighted poor management decisions.

"[McConachy] had options of trading stock, buying supplementary feed, and chose to do nothing," the vet said.

"[He] demonstrated a complete lack of care for all stock on this property for a number of months and failed to rectify feed issues.

"With the carcasses around he must have seen the harm he was causing."

McConachy is free without bail conditions until his sentencing.