Protection and indemnity insurer Britannia P&I has hit back at claims from the Australian Maritime Safety Authority (AMSA) that it has abandoned 60 containers lost from a Yang Ming Marine Transport boxship on the seabed.

Around 60 of 81 containers, which were lost from the 4,250-teu YM Efficiency (built 2009) off the Newcastle-Port Stephens coast following a storm in June last year, have yet to be recovered and are sitting at the bottom of the sea.

The AMSA has signed an AUD 15m ($10.1m) contract with salvage company Ardent Oceania to recover the containers.

The organisation claimed the recovery job should have been arranged and paid for by Taiwan's Yang Ming and its insurer, Britannia.

But in a response to TradeWinds, Britannia said it had acted correctly following the casualty and quickly arranged for the cleanup of containers and debris that had washed ashore at a cost of $3m.

The club pointed out that the local Australian state government had earlier described its immediate response to the casualty as an example of “best practice”.

However, Britannia explained that it believes attempting to recover the remaining containers from the seabed would risk causing additional environmental damage.

“Having taken expert advice about the remaining containers which are lying on the sea floor, Yang Ming and Britannia P&I have been advised that attempting to remove them will cause more environmental damage than leaving them in place due to the fact that they are in deep water [about 120 metres] with a large proportion substantially buried by sand and many lying outside of the Australian territorial sea,” a Britannia spokesperson said.

“At every stage during this operation, Yang Ming and Britannia P&I have shared third-party experts’ reports on the best way forward with AMSA and the local authorities.”

However, AMSA has insisted that the containers remain a pollution threat to the Australian coastline and must be recovered.

“These containers are filled with plastic and if they are not removed then they will continue to degrade, periodically releasing their contents to wash up on the Hunter Region's beautiful beaches,” AMSA chief executive Mick Kinley said.

“If not dealt with now in a controlled manner, this will be a pollution legacy that future generations will have to deal with for decades.”

The salvage operation to recover the containers is due to start in March. The AMSA has said it will seek to recover the full cost from Britannia.