Over the last three weeks, concerned members of the public have approached the RSPCA about the issue.

Victorian senior inspector Lisa Weston said the horses being investigated were either suffering from old age or suckling foals.

Some (horses) are in good condition and others are in poor body condition, she said.

The increased energy burden placed on the horses was making them skinny, she said.

She said there was a lack of natural feed available because of the drought and the high cost of feed.

The RSPCA is working with the owners to get the horses out of immediate danger.

Ms Weston said the RSPCA was also working with the owners to improve the horses' condition in the long-term.

She said investigations would also continue into whether there had been any breach of the prevention and cruelty to animals act.

Ms Weston said the RSPCA was implementing a management plan which involved destocking.

Destocking is an important part of managing stock like this, she said.

Ms Weston said RSPCA inspectors would closely monitor the horses in the area.

She said the RSPCA had received 45 per cent more complaints than the same time last year.

We will continue to ensure the animals are given the care they deserve, she said.

Anyone with concerns about the condition of any animal should contact the RSPCA on 9224 2222 or go to www.rspcavic.org