The deaths of five men killed in the 2023 Loafers Lodge blaze in Wellington were avoidable, a jury has been told.

The Crown has opened its case against four people facing manslaughter charges over "layers of failings" in management of the budget accommodation's fire safety system.

Gregory Bruce Mein, 73, Barry Charles Collins, 76, Glenn Brendan McAllister, 59, and Marie Louise Murphy, 71, appeared in the High Court at Wellington on Monday.

Esarona Lologa was last year sentenced to life in prison after being found guilty of murder and arson for deliberately lighting the fire on May 16, 2023 that killed Michael Wahrlich, Melvin Parun, Peter O'Sullivan, Kenneth Barnard and Liam Hockings.

According to the Crown, Murphy was the lodge's part-time property manager, while Mein was the director. Both McAllister and Collins were residents who had access to the fire safety system.

The four each face five charges of gross negligence causing death. They also face, in the alternative, five charges of breaching health and safety, thereby committing manslaughter.

A jury of five men and seven women heard the first of the Crown's opening address on Monday.

Prosecutor Stephanie Bishop told jurors that while Lologa lit the fatal fire at 12.12am on May 16, the trial would cover why it took 12 minutes for a 111 call to be made, 13 minutes for the fire safety system to activate, and why an alarm only sounded on the lower floors.

She said minutes and seconds mattered. "Flames more fast, smoke even faster."

That night, firefighters arrived to a chaotic scene, she said, and reports of people trapped on the upper levels of the three-storey building - but after evacuating some residents, they were forced to withdraw for safety reasons.

"The Crown says that if the building's fire safety system was working as it should have been, the five residents who died would have had the opportunity to escape and would have likely survived."

She said alarms were frequent at the building - which housed about 90 people, mainly men of lower socio-economic status - but over the years fire safety systems had degraded.

"Years prior to the fatal fire a practice emerged at Loafers Lodge allowing residents to both silence and also reset the fire alarm system.

"And that was, the Crown says, done in an attempt to save costs."

Bishop said this practice took place under the authority of Murphy, the property manager.

As director of the lodge, she said Mein held overall responsibility and had a duty to ensure the fire safety system worked.

Bishop said the fatal fire in the early hours of May 16 was the second lit by Lologa that night.

She said the first fire activated the fire safety system as it should, sounding alarms and closing fire-proof doors.

Collins - just one of the residents who had access - silenced the alarm but did not investigate the cause, she said.

McAllister, described as the building's fire warden and Murphy's second-in-charge, would reset the system, Bishop said, but did not do so that night, allowing the second fire to spread undetected.

She said when McAllister was finally roused by residents from his room, he called 111.

Bishop said Collins carried out his duties on a voluntary basis, while McAllister did so for cash.

She said there was no evacuation procedure in place at the lodge and it was left up to residents to alert emergency services.

The building's fire alarm system was not connected to automatically alert Fire and Emergency or monitored by an independent company, she said.

"It should have been.

"The Crown says that this is a case of layers of failings of management and those who held a quasi-management and fire warden role.

"These failings were both systemic and long-standing they were also specific on the night of the fire."

The Crown is expected to continue its opening statements on Tuesday, followed by the defence.

The trial is set down for eight weeks.