The pile of timber and building waste stretches almost 10 metres and is the latest illegal dump to taint the Illawarra escarpment.

The rubbish pile was discovered on the western side of the Old Princes Highway, south of Boomerang Golf Club, at Maddens Plains and taped off on Tuesday.

A council sign nearby warns illegal dumping is an offence and carries a maximum penalty of $1 million.

This threat does not seem to have concerned the illegal dumpers, who have helped themselves to the site, thumbing their nose at the council’s regulations with their placement of the rubbish.

The council itself is in hot water over its own roadside dumping debacle.

It is investigating how it came to dump many loads of asbestos-contaminated waste on the roadside, during an ‘‘initiative’’ to create mounds of waste to block illegal dumpers from certain locations.

At first the council decided to investigate itself but was later forced to call in the government’s Internal Audit Bureau as well.

The Environment Protection Authority is also investigating the council’s actions.

The issue was brought to light after a Stanwell Tops resident asked the Mercury to investigate why the mounds were appearing along the Old Princes Hwy.

While the mounds have now been fenced off pending their removal, the signage on the fences makes no mention of asbestos, merely saying ‘‘do not disturb the soil’’.

A council spokesman said council was investgating the latest dump site.

‘‘Illegal dumping costs council approximately $420,000 this financial year and more than $1.7 million over the past five years,’’ he said.

‘‘This is a cost direct to ratepayers.’’

While the council is ‘‘working with’’ the EPA to finalise a plan for removing the contaminated mounds, it has refused to answer questions about where the waste will be taken.

Council has said it would not be answering any more questions about the dumping until its investigation is complete.