Testing is underway after a large quantity of restricted waste, containing asbestos, was illegally dumped at Kulnura.
Strike Force Dothan has been investigating anomalies in the City of Sydney's Green Square Town Centre development.
Instead of going to one of two approved sites, it's alleged up to 17,000 tonnes of waste appear to have been dumped or disposed of illegally.
This morning, investigators and the EPA executed a search warrant at a property on Cherry Lane, with the owners telling the officers they were advised the material was clean fill.
Samples will now be analysed and it's anticipated large scale remediation will be required.
Investigators believe the illegal dumping operation is linked to organised crime.
A 48-year-old man is already before the courts, after being charged with numerous offences by Strike Force Dothan investigators, including fraud offences totalling almost $4 million relating to the illegal dumping of asbestos.
Investigations continue into the matter and police have urged anyone with information about illegal dumping to come forward.
Anyone with information about this incident is urged to contact Crime Stoppers: 1800 333 000 or https://nsw.crimestoppers.com.au. Information is treated in strict confidence. The public is reminded not to report crime via NSW Police social media pages.