The alleged case of animal cruelty first came to the attention of the RSPCA in March and since then inspectors have visited the property in Neville five times.

There were 90 horses on the property at the first inspection, but since then some older horses have been euthanised - not by the RSPCA - while others have been sold.

The charity's spokeswoman said while there was evidence of supplementary feeding during each inspection, the owner was still issued with a written order.

"Written directions have been issued to the owner of the horses in relation to improving their condition and increasing supplementary feeding and de-stocking to ensure increased welfare outcomes for the horses," she said.

The RSPCA spokeswoman said the ownership and day-to-day care of the horses had become a "complicated legal situation" and a social media group had made the situation more difficult.

The Facebook group, called RSPCA Fail, has written numerous posts since Tuesday claiming horses are starving, donations of feed are needed and that the RSPCA had failed to act.

The RSPCA spokeswoman said there was a lot of "misinformation being spread online".

"When people form social media lynch mobs, and encourage others to take the law into their own hands, it impacts negatively on our capacity to do our jobs," she said.

"It can jeopardise prosecutions, have consequences for sentencing outcomes and endanger public safety."

As a charity she said the RSPCA had limited resources, but she was confident that inspectors were "working diligently, in accordance with the law, towards better outcomes for these horses".

The spokeswoman said the RSPCA had offered its support to de-stock further via private sale or rescue groups.

RSPCA Fail did not respond to a request for comment.