The three week expedition in the Mt Arthur area near Murchison, cracked the 1000 metre mark and catapulted New Zealand's deepest cave into the Top 10 in the world.
Cracking that mark means the New Zealand cave system is not only much deeper than first thought, but also connected.
Caver Kieran McKay, who was part of the team that broke the new record, says the find has taken a long time.
"We've been looking for this for over 60 years and it's involved hundreds and hundreds of people and thousands and thousands of man-hours and people traipsing all over Mt Arthur," he says.
The latest expedition linked separate caves in the Ellis Basin system to form what will be in the Top 10 deepest caves in the world.
"We're walking into worlds that formed before mankind ever existed on this planet and our lights are lighting up the darkness for the first time and that to me is an incredible humbling and amazing feeling," says McKay.
McKay is an experienced caver, who knows the cave system well. A 10 metre fall in 1998 left him with a smashed jaw, wrecked knee and broken arm. It took him three days to be pulled out, but it never stopped him going back.
That determination has been rewarded with his team's latest find and McKay says the cave system may go even deeper.
"There's an entrance 300 to 400 metres higher up the mountain and we're hoping to connect that into the system as well," he says.
The Sparc-funded team will be heading back next summer to find out just how deep they can go.