Cavers have discovered what is believed to be New Zealand's first cave system more than 1km deep in a mountain west of Nelson.
The team of three cavers, Kieran McKay, Aaron Gillespie and Troy Watson, made the connection between two known caves in the Ellis Basin, on Mt Arthur in Kahurangi National Park.
The system went from 775m to 1026m with the discovery and is now one of the top 80 deepest caves in the world but with a bit more work it should get into the world top 10 next summer, Mr McKay told the Nelson Mail.
Until now Nettlebed Cave, also on Mt Arthur, at 889m, was New Zealand's deepest cave system. The new system is 33.4km long - making it the second longest cave in New Zealand after the Bulmer Cavern on nearby Mt Owen, which is 66km.