The slip happened overnight Saturday (4 May 2019).
Rocks and debris blocked a culvert across a creek at the Milford Sound cruise boat terminal carpark, causing surface flooding in the Freshwater Basin area.
All people in the area have been accounted for and there are no reports of injury.
“Our first priority is ensuring the location is secure and making sure anyone in the area is safe,” says DOC Te Anau Operations Manager Nedra Burns.
“People booked on any Milford Sound cruises should contact their tour operator.”