It took attempts by two salvors to successfully bring the purse seiner back up to the surface this week, almost a month after it first became partially submerged.

The local vessel was carrying 50 tonnes of salmon when it began taking on water at the middle wharf of Eden Port and despite efforts of Fire and Rescue NSW and the owner to try to prevent the partially submerged boat from sinking further, it was inundated with water and went to the bottom.

A Port Authority of NSW spokesperson said Port Authority had been overseeing the salvage and closely monitoring every stage of the recovery process to protect the local marine environment.

"The vessel has been raised and is stable and all oil has been removed from the vessel," the spokesperson said.

"An operation is now underway by the salvors to remove the fish and steps have been taken to minimise potential odour during this process."

There were concerns about fish on board coming out of the sunken vessel, as well as thousands of litres of diesel and oil and Port Authority said it worked closely with the owners and salvage company to ensure around-the-clock monitoring, "to protect the environment by continuous checks for leakage or seepage ensuring no major pollution incident occurred".

In response to the incident booms were placed around the vessel quickly after it capsized, which Port Authority said captured the small amount of pollution and seepage that escaped from the vessel.

"This has been absorbed and removed along with any floating items. Any items on the seabed have also been removed by divers," the spokesperson said.

The booms will remain in place until the fish are removed from the vessel as an added precaution.

Port Authority would like to thank the range of agencies it has worked with throughout the operation including Fire and Rescue NSW, the Environment Protection Authority and Australian Maritime Safety Authority to minimise the impact on the marine environment and to ensure the salvage of this vessel was undertaken safely and appropriately.

Polaris Marine was the second company to try to float the sunken Janet, and succeeded using the Molly Grace on station with a winch.

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