NZ First has raised the possibility the Interislander ferry Aratere ran aground after someone onboard the vessel “put the autopilot on, went for a coffee, and then couldn’t turn the autopilot off” when they returned.

Maritime New Zealand has described the “conjecture” as being “unhelpful” amid an ongoing investigation. The Interislander vessel ran aground shortly after leaving Picton on June 21, due to what authorities described as a “steering failure”.

While Aratere was later re-floated, the incident raised questions about the Government’s decision to cancel an order for replacement ferries after a cost blow-out last year.

NZ First’s claim, published from an official X account, was posed as a question.

“Is it true that the Aratere ran aground when someone put the autopilot on, went for a coffee, and then couldn’t turn the autopilot off in time when that someone came back?

“If so, why haven’t the public been told that?” the post read.

Deputy Prime Minister and party leader of NZ First, Winston Peters, is currently the acting prime minister while Christopher Luxon travels to the US.

1News has approached NZ First for further comment.

In response to the post, Interislander executive general manager Duncan Roy said there were a “regulated number of qualified people” on the Aratere’s bridge on the night of the grounding.

“We would not normally respond to speculation while an investigation is underway.

“However, we can say that there is a regulated number of qualified people who need to be in attendance on the ship’s bridge at all times, and we meet this without exception — including on the night of the grounding,” he said in a statement.

Meanwhile, Maritime New Zealand suggested that “conjecture about the cause of the grounding was unhelpful” as investigators were continuing to look into it.

The Picton Habour tugs played a key role in refloating the ferry after it ran aground on Friday night.

“The cause of the incident is currently being investigated by both Maritime NZ and Transport Accident Investigation Commission,” a spokesperson said.

At the time of the grounding, KiwiRail said work had just been completed on the Aratere, including the replacement of the steering mechanism.

“We pre-emptively replaced the steering mechanism with a brand-new system.”

Eight commercial vehicle drivers and 39 crew were on board at the time of the incident. with the ferry carrying commercial trucks and general freight.

The Aratere has a colourful past — with mechanical problems starting the day after its first sailing

Officials said KiwiRail was “pretty disappointed” with the grounding, considering the amount of maintenance work that had been recently completed on the vessel.

However, they also defended the reliability of the ferries, with chief executive Peter Reidy saying they had “99.6% reliability” in the last six months.

The grounding marked the latest in a series of incidents which have plagued the vessel in its 25 years crossing the Cook Strait.