Yang Ming Marine Transport says a containership arrested in Australia over the weekend has been released.

Australian authorities detained the 4,250-teu YM Eternity (built 2009) on Sunday in a bid to recover clean-up costs of up to AUD20m ($13.4m).

The arrested vessel is a sistership of the 4,250-teu YM Efficiency (built 2009), which lost 81 containers in gale-force winds off the coast of Newcastle and Port Stephens in June 2018.

Yang Ming said the ship was released on Monday and normal cargo operations were said to have “resumed immediately”.

“Yang Ming regrets any inconvenience to Australians and apologizes for the conduct of Australian Maritime Safety Authority (AMSA) in arresting the YM Eternity in a way that caused unnecessary and maximum inconvenience to Sydney customers without any notice,” Yang Ming said.

AMSA claims that Yang Ming had “refused to pay for the clean-up of the remaining pollution including the containers and their contents” which have been located on the seafloor off the coast of Newcastle.

Yang Ming has disputed the claim arguing that its insurer “responded quickly and effectively” to the incident with the immediate allocation of “very significant resources and manpower” to the loss of the containers and their contents.

“Yang Ming has been ever since committed to keeping the Hunter Coast pristine and working with the New South Wales Government to ensure all debris that could possibly be associated with the incident is cleaned up within hours of it being reported – even if it was not actually from cargo on the ship,” the shipowner said.

Yang Ming said it had organized for sonar scanning of the sea floor after the incident and that this has continued subject to weather and safety considerations.

A total of 60 containers have been identified, while a further 16 are still missing. Five containers have been recovered.

“All of the containers lying on the sea floor are in deep water – about 120 meters – with most of the containers lying outside of the Australian territorial sea,” Yang Ming said.

It added that, based on expert advice, any attempt to remove the containers would cause “more risk of environmental damage than leaving them in place”.

“The operation to remove the containers would result in plastics within the containers being released into the ocean,” it claimed.

“As a consequence, these experts have recommended, considering all the environmental factors, the containers are best left on the sea floor pending further monitoring.”

In December, AMSA signed an AUD15m contract with Ardent Oceania for clearing up the 60 containers. Work begins in March and is expected to be completed within a month.