All athletes are "safe and well" after a mass rescue effort was triggered near Arrowtown in Central Otago.
Six people were airlifted to hospital and are in stable condition.
The people were taking part in a marathon and suffered hypothermia due to weather conditions in the area.
The Rescue Coordination Centre (RCCNZ) said in a statement they were first alerted to a developing situation following a beacon activation at 1am Wednesday in the Macetown area, around 15km from Arrowtown. As of 9am, a total of nine beacons were activated.
RCCNZ operations manager Michael Clulow said they have so far airlifted six people from the area, transporting them to Queenstown Lakes Hospital. These people evacuated were suffering from mild hyperthermia.
A Te Whatu Ora Southern spokesperson said five people have hypothermia and one person has moderate injuries. All patients are stable.
The Southern Lakes Ultra Marathon is currently running in the area. Clulow said at least 110 people are in the area associated with this event.
There has been heavy rain in the area, causing the Arrow River to rise and the weather is forecast to remain inclement over the next 24 hours.
A Metservice heavy rain watch is currently in place for Otago, with heavy rainfalls possible.
Clulow said this is a complex response, and they are working closely with search and rescue partners and the race organisers to understand the needs of the people in the area.
RCCNZ has since established communication with the race management and is working through where people are, and what their support needs may be.
A police spokesperson said police are aware of a rescue operation being led out of Macetown and are liaising with Rescue Coordination Centre which is leading the response.
In an update just after 1pm , Southern Lakes Ultra Marathon said all athletes and crew have been accounted for and are safe and well.
The Southern Lakes Ultra Marathon is a sold-out seven-day race done in six stages. On Wednesday the participants are expected to complete stage three.
The event states it caters to everyone "from Elite to First Timers".
Earlier on Wednesday, the Southern Lakes Ultra Marathon confirmed on Facebook the rescue operation is underway for participants and crew.
"I am in great communication with multiple organisations and agencies and at this stage all athletes are safe, well and accounted for," spokesperson Emily Sutton wrote.
"Rescue operations NZ are sending individuals into Macetown to organise a plan.
"Some runners have been evacuated out of the mountains and they are being cared for by crew and staff at Queenstown Lakes Hospital. These athletes are being well supported and are currently under observation.
"If there is any concern individual families will be notified by me directly. As you will all understand this is a very stressful time so please hold off messaging directly.
"I will continue to provide communication with you all where possible and I can ensure you that I am doing my absolute best to ensure the health, safety and well-being of these athletes remains our top priority."
