Upgraded safety equipment installed at Fiordland's Homer Tunnel was put to good use when a tourist bus caught fire near the tunnel.
The Kiwi Experience bus burned to a shell on Thursday night, but the 22 tourists it was carrying escaped without injury.
Sergeant Tod Hollebon of Te Anau police said the bus driver contacted emergency services about 5pm using the tunnel's satellite phone.
The phone and fire extinguishers were installed in the tunnel after another tourist coach caught fire in the tunnel in 2002.
Te Anau Fire Brigade senior station officer John Henwood said the bus was still smouldering when firefighters arrived at the scene, about 500m from the Milford Sound entrance to the tunnel, about 6pm.
High-pressure hoses were used "to cool things down".
Mr Henwood said the driver had done exceptionally well to get all passengers and their valuables off the bus.
"He was lucky he stopped where he did," he said.
EX Group general manager Sue Sullivan said the bus had been on a day trip from Queenstown to Milford Sound.
Its 22 passengers were from several countries.
In the 2002 fire, a Ritchies Coachlines bus carrying 32 Singaporean tourists burst into flames soon after entering the tunnel, damaging the inside of it.
The fire prompted improvements to safety facilities in the tunnel and medical facilities at Te Anau.
A Kiwi Experience bus plunged down a steep 30m bank between Fox and Franz Josef glaciers on the West Coast in April, injuring 10 of the 43 passengers.