The notice was issued to Esso, its local subsidiary.
The Marlin Complex consists of the Marlin A and B platforms joined together by a walkway in VIC/L03, approximately 42km off the Gippsland coast.
NOPSEMA published an OHS Improvement Notice to Esso on December 23, it is contravening clause 9(2)(a) to the Offshore Petroleum and Greenhouse Gas Storage Act 2006 and that the health and safety of personnel was at risk.
The regulator conducted an inspection of the site between November 29 and December 1 and found Esso's cleaning program was not up to standard based on Victorian Department of Health requirements as adopted by the company's COVID Safe Plan in August last year.
The notice said Esso failed to provide objective evidence that it was complying with their COVID Safe Plan since November, 2020.
The Victorian Health cleaning guidelines require companies to take all reasonable steps to frequently and regularly clean and disinfect frequently touched points in shared spaces, with cleaning programs to escalate depending on the level of community transmission of COVID-19.
The regulator said Esso had identified the need for deeper cleans in its August COVID Safe Plan however no evidence was provided that it was actually following the rules it had set for itself.
NOPSEMA said Esso advised that since November 26, it had moved from a "Hot Standby" operating mode to a "Preparation" mode, which only requires "routine cleaning", however a risk assessment has not been provided to demonstrate the removal of enhanced cleaning practices.
"By not having an appropriately enhanced cleaning programme in place for cleaning and disinfection of high touch surfaces, there is a higher risk of potentially infective respiratory droplets/aerosols landing on a surface and transmission," the notice said.
Esso had 14 days from the date of notice to comply and ensure the enhanced cleaning programme is implemented and documented evidence is provided.
A NOPSEMA status update has noted the company has complied with the notice.
An Esso spokesperson told Energy News "we addressed the regulator's concerns and have implemented enhanced COVID-19 cleaning and disinfection at the Marlin Complex and other Esso facilities in the Bass Strait".
"We are confident that the process and controls we have in place will protect the health and safety of our workforce and ensure the continued supply of essential energy to our customers," he said.
It is the latest order Esso has been given by the regulator over multiple health and safety issues across its ageing infrastructure offshore Victoria which it is expected to decommission within seven years.
In October last year it was issued three separate directions, more serious than a notice, after investigators found workers were afraid they would lose their jobs if they raised safety concerns after a flashfire onboard the Kingfish B platform left one worker with burns to his arm and hand.
The platforms are part of the wider historic Gippsland Basin Joint Venture operator Exxon shares with BHP. Woodside will take over when its acquisition of the latter's petroleum business completes this year.