An Auckland charter vessel operator has been ordered to pay a $140,000 emotional harm reparation after the death of a woman who fell overboard.

Danielle Tamarua and her work colleagues were guests on board the luxury charter boat Zefiro for a trip around the Hauraki Gulf on April 1, 2021.

The 25-year-old had gone up to the bow of the vessel with another passenger when the weather worsened. Tamarua was heading back inside the boat as it returned to berth at the Viaduct when she slipped and fell overboard.

Tamarua was struck by the vessel and died of her injuries.

A second person jumped in to try and save her but was unsuccessful. They were uninjured.

The vessel's operator of 17 years, Zefiro Charters Limited, was today sentenced in the Auckland District Court for a breach of the Health and Safety Work Act 2015.

In a media release, Maritime NZ said the company failed to ensure health and safety policies were correctly followed, which played a key role in her death.

Dwen said while the company had policies and procedures in place under the Maritime Transport Operator Plan (MTOP) to keep passengers safe, they were not followed on the day of Tamarua's death.

The plan identified various health and safety risks, including the hazard of passengers being on the bow of the vessel while it is underway. Ultimately, the company failed to ensure the systems and processes in the MTOP were properly implemented and enforced on board.

It also included a safety briefing stating passengers "were not allowed on the bow, side decks or the duckboard (the very rear of the boat) while it is underway", Maritime New Zealand investigations general manager Pete Dwen said.

"Some crew were unaware it was a policy for the vessel."

Maritime NZ also noted there was a lack of physical barrier for the passengers indicating the "no-go" areas.

Dwen said had the health and safety procedures been followed, "this incident would have likely been avoided".

"This should have been a fun day out on the water. This incident is a horrific example of what can go wrong when a company fails to ensure health and safety procedures are followed.

"I want to offer our sincere condolences to the family and friends of Ms Tamarua, as well as those on-board the Zefiro on 1 April, 2021."

He also thanked the emergency service personnel who responded "quickly and professionally to a very difficult situation".

Judge Thomas described the culpability as amounting to a significant breach and indicated he would have had no hesitation in imposing a significant fine in the hundreds of thousands of dollars.

However, due to the limited financial means of the company, Judge Thomas ordered emotional harm reparations of $140,000 to be apportioned between the victims only.