The state's environmental watchdog is refusing to release contamination reports to a Sydney landlord in dispute with his former tenant Woolworths over clean-up costs at a petrol-station site.

The Environment Protection Authority sided with the supermarket giant, which argued the reports should not be released because they could affect its commercial interests.

Emmanuel Stratiotis has been struggling to get information from the NSW Environment Protection Authority about the contamination levels at the petrol station site he owns, previously run by Woolworths. Credit:James Brickwood

Emmanuel Stratiotis, whose family owns the land, said the information was critical to answering who should pay for the remediation bill, which he calculated at more than $1 million.

"It is easier to pull Excalibur from the stone than to get an answer from these guys," Mr Stratiotis said of the authority.