Tasmania’s Environmental Protection Agency (EPA) is considering its legal options after it was refused access to inspect Diamond Offshore’s semi-submersible Ocean Monarch for marine pests.

The rig is currently moored in Tasmania’s River Derwent for maintenance and minor repairs following a drilling campaign off Victoria in the Gippsland basin.

EPA director Wes Ford confirmed he had contacted Diamond Offshore in November to discuss the need for a visual inspection of the rig’s hull.

The EPA was wanting to check for the presence of marine pests such as the introduced Colonial Sea Squirt which is now found off Western Australia, where the rig had been operating prior to the Gippsland campaign.