About three metres of land have been lost in a day in Bluecliffs. Photo: RNZ / Tess Brunton
The Waiau River mouth has been successfully opened, away from Southland properties at risk of eroding into the sea.
A state of emergency remains in place after rapid erosion from the sea and river threatened properties in the Bluecliffs village, with about three metres of land lost in a day.
Urgent work to direct the flow of the river away for homes started last week, but it was put on hold for a few days due to safety concerns.
Late on Thursday, contractors cut through the bar after moving roughly 30,000 cubic metres of material.
Southland Civil Defence Group Controller Simon Mapp said the the opening would hopefully reduce the erosion and give the community time to talk about its future.
He warned people to avoid going near the new river mouth.
"The area around the new opening in the bar east of Bluecliffs is extremely dangerous, so please do not go onto or near this area. Some access points around the area are still restricted for safety reasons. Please continue to avoid any unnecessary travel to the area while this state of emergency is in place," he said.
"The opening was a highly complex and technical task, and all precautions for the safety of those undertaking it were planned for. Given the complex and dynamic environment at Bluecliffs it's unknown how successful this opening will be or for how long it may last."
Meridian Energy planned to gradually increase the release of water from its hydro lakes over the next two days.
"We are currently awaiting the weekend's increased river flow and incoming weather to determine the effectiveness of the bar opening," Mapp said.
"This work has always been a struggle against Mother Nature, and the team has done a commendable job despite difficult circumstances."
Work to remove material from an old community tip was expected to start in the next few weeks.
A state of emergency was first declared on 8 February.