The Dunedin City Council says it is looking for the culprit.
Saddle Hill Community Board member Scott Weatherall said what appeared to be a full trailer load of the hazardous material had been dumped in the picturesque location intentionally.
It stopped people from enjoying the area, put people at risk and cost all council ratepayers, who would paying for the clean-up.
"First and foremost it’s just no good that somebody’s dumped this stuff — let alone how dangerous it is.
"We acknowledge that not just anyone can come and pick that up.
"It actually takes specialist crews to clean up, crews to come and do that.
"It costs us, the ratepayers, to do that.
"We’re somewhat sympathetic that going to the tip costs money but, equally, it’s probably as cheap as it’s been for a long, long time now and this just needs to be disposed of appropriately."
Photographs of the illegal dumping taken by Mr Weatherall’s father were posted to social media where they garnered hundreds of largely negative reactions.
A council spokesman said the last of the material was expected to be cleared from the site by specialists yesterday.
This was the fourth similar incident in the last month and the council was working to determine who was responsible.
The risk from the material came when it was cut, handled or left to deteriorate.
For this reason the council had contracted a specialist contractor.
The council preferred a public education approach with warnings for first-time and minor offences.
But fines of up to $400 for repeat offenders and significant incidents were possible, the spokesman said.
Prosecution was also an option for the most serious incidents.
