Queensland's groundwater is at risk of being contaminated by leaks from rusting coal seam gas wells in the state's west, activists warn.
Several wells owned by Origin Energy and Shell experienced leaks and failed pressure tests.
They were then abandoned according to state government documents obtained by the Lock the Gate Alliance.
Resources Safety and Health were notified of potential leaks from two of Shell subsidiary QGC's wells in the Jordan tenement, south of Chinchilla, in early 2021.
After one well failed a pressure test the next was tested under the same means.
Both were abandoned, but it's unclear if plans to seal went ahead.
AAP has sought comment from the Department of Environment and Science.
Lock the Gate Alliance co-ordinator Ellie Smith says well leaks due to rust could be widespread in Queensland, creating a high risk of groundwater contamination.
"This is what we've always feared: that piercing the underground water layers that sustain the Western Downs like a pincushion with thousands of CSG wells is putting water quality at risk if well corrosion occurs," she said in a statement on Tuesday.
"We know that well corrosion is a major risk in the long term but it's even more shocking to see that it is already occurring in Queensland gas fields. This is a serious threat to farmers who rely on shallow aquifers to grow the food and fibre for Queenslanders."
Shell said it was committed to ensuring the integrity of their wells to a high standard.
"We carry out regular maintenance to ensure that infrastructure remains safe and strong, and have a well integrity management system in place where wells are regularly tested," a spokesperson told AAP in a statement.
"Any well integrity incidents or issues are investigated immediately and reported to the relevant regulators in accordance with our obligations."