It comes after an inspection of the APL England found that "lashing arrangements for cargo were inadequate" and "securing points for containers on the deck of the ship were heavily corroded", the Australian Maritime Safety Authority said.

"These findings constitute a clear breach of a requirement under SOLAS to ensure that a ship and its equipment are maintained so as not to present a risk to the safety of the ship itself or anyone on board the ship," AMSA general manager of operations Allan Schwartz said.

"The detention will not be lifted until these serious deficiencies are rectified. That is now a matter for the ship's owner, American President Lines, and operator to rectify.

"These findings will form part of AMSA's ongoing investigation and, while we do not want to pre-empt the outcomes of that investigation, it is already clear that the risk of this container loss occurring could have been reduced."

Mr Schwartz said AMSA expected the ship owner and its insurer, Steamship Mutual, to take full responsibility for remediating any impacts of the incident, which occurred in heavy seas about 73 kilometres south-east of Sydney.

"We're pleased to hear news today that the insurer is engaging contractors to retrieve some of the floating containers," Mr Schwartz said.

A shoreline clean up continues along the NSW coast. Five containers that lobbed on Birdie beach near Budgewoi are understood to have been removed on Thursday.

Members of the public and contractors engaged by NSW Maritime, which is managing the onshore clean up, have removed thousands of surgical face masks from multiple Central Coast beaches.

The APL England spilled the cargo after losing power and rocking in heavy seas on Sunday.

The incident is almost identical to how the YM Efficiency spilled more than 80 containers off the Hunter coast on June 1, 2018.

An Australian Transport Safety Bureau investigation found that ship's load had not been secured properly.

The $17 million operation to retrieve 63 of those containers finished earlier this month.

The Australian Maritime Safety Authority is locked in a court battle to have Taiwanese company Yang Ming pick up the bill.