The Prelude FLNG facility produces natural gas from an offshore field approximately 475km north-north east of Broome and last weekend shipped its 15^th cargo of LNG.

This morning the National Offshore Petroleum and Environmental Management Authority (NOSPEMA) ordered Shell not to conduct "intrusive activities" to certain parts of the plant and equipment aboard the Prelude over fears there could be a loss of hydrocarbons from the facility.

There is no immediate threat or risk to workers or the environment.

Energy News understands NOPSEMA issued Shell the direction over process concerns, not maintenance or mechanical problems.

In a statement to Energy News, Shell Australia said production had not been affected and the vessel was still operating safely.

"Shell has received a direction from NOPSEMA, the Australian regulator, regarding certain work activities on Prelude," a spokesperson said in a statement.

"As a result, activities related to isolations of the plant and equipment have ceased except where required for safety reasons. A detailed review of the controls is now being undertaken to identify gaps to be addressed."

Shell has been working with NOPSEMA for several months to rectify its processes around isolation activities.

Before any plant is inspected, maintained, cleaned or repaired, where practicable, it must be shut down and its energy sources locked out and tagged as part of an isolation procedure.

However, NOPSEMA has raised concerns that Shell has not ensured "best practice" and has demanded the company put in place new isolation procedures within 60 days.

In its notice, it also said Shell senior management would be required to attend a meeting with the regulator to prove it had made the changes.