Warrnambool trainers have been blocked from using one of their best weapons in the preparation of their racehorses.

The sand dunes at Levys Point are off limits following advice to the Warrnambool City Council from Aboriginal Victoria there were Aboriginal Protected places in the area.

Jane Baker, secretary of the South West Owners, Trainers and Riders Association, said there could be significant fines for the council if trainers continue using the dunes.

Premier Victorian trainer Darren Weir has been a regular user of the beaches at Warrnambool and used them to prepare Prince Of Penzance to win last year's Melbourne Cup.

"We understand council's position that they've had to close it immediately because they will be liable if there is anymore damage occurring," Baker told RSN927.

Baker said the ban on using the dunes had been unexpected.

She said trainers had been issued with maps of trails to use among the dunes and she believed they were sticking to them.

"There's been no warnings, no signs, there's nothing in the regulations to prevent us going through those trails," Baker said.

"There are probably some heritage sites at several places around here but the fact the council has issued permits to us in the past would indicate they didn't know either.

"What we need to determine is exactly where these places are and what we are looking for.

"It's very hard to avoid something if you don't know it's there."

Baker said at least 30 horses a day used the trails and most of the trainers in the association, of which there are upwards of 30, would use the beach at some time.

The council has also instructed trainers to work horses in smaller groups at Lady Bay and on the wet sand near the waters edge.

Baker says council is worried about erosion to the beach and also public safety.

Racing Victoria's racing operations manager Paul Bloodworth says hopefully a solution can be found between the government, Warrnambool council and local trainers as the beach is a vital part of the training program for a number of leading trainers including Weir..