Real Journeys has bought four automated external defibrillators for company boats operating in remote parts of Fiordland.
The portable defibrillators will be kept on the Doubtful Sound boats Patea Explorer and Fiordland Navigator and on the Milford Sound overnight cruise boats Milford Mariner and Milford Wanderer.
All overnight boat crew and company staff trained in first-aid will be trained in their use.
Real Journeys Milford Sound-Doubtful Sound area manager Paul Norris said the ZOL AED-plus defibrillators were designed so even novices could effectively deliver defibrillation and CPR.
Having an AED (automated external defibrillator) can increase the chances of survival by up to 40% when dealing with a sudden cardiac arrest.
"It's quite a big investment, but it's an investment in the wellbeing of our passengers and staff. You can't put a dollar value on that," Mr Norris said.
The Milford Sound Development Authority has a defibrillator available in the main terminal building in Milford Sound.
However, Real Journeys has decided to make defibrillators available on boats used for overnight and multiday cruises because of the remote areas in which they operate.
"If someone needs a defibrillator, you don't have much time to get one to them," Mr Norris said.
"Having a defibrillator on board could be literally the difference between life and death."
The nearest defibrillator to Doubtful Sound is at the Manapouri underground power station, across Wilmot Pass.
