Defence attache to South Korea Colonel Donald Jones confirmed on Facebook that Anna Song (36), her son Taeyang Rikiti (2) and mother Rose Kim (65) were killed by a landslide in Gapyeong, Gyeonggi Province amid torrential rain.
The Victoria University alumni studied English literature in Wellington, before moving to Rotorua, where she worked as a banking manager for ANZ.
Her son was born in Rotorua.
She returned to South Korea with Taeyang in 2018 to help her mother run her tourist accommodation in Gapyeong.
She also worked for the New Zealand Chamber of Commerce in Korea.
Jones shared a tribute in the wake of the tragic news.
He recounted staying at the family's guest house in June.
"Corinne and I had a lovely weekend staying there recently... it was a beautiful setting among the forested hills, and the three of them seemed so happy there," he wrote.
"My thoughts and prayers to her brothers and the Rikiti whānau in NZ."
He said Song was busy organising the upcoming New Zealand Tech Roadshow for the Chamber of Commerce and "was all-a-buzz when we caught up for dinner last month when she was in town for filming NZ and Korean tech business leaders for that".
Local media reported the bodies of the missing trio were recovered on Monday, local time.
A spokeswoman for the Ministry of Foreign Affairs and Trade and the New Zealand Embassy in Seoul said they were aware of the deaths and were providing consular assistance.
More than 1000 people in South Korea have been forced from their homes after days of heavy rain caused floods in South Korea. At least 13 people are reported dead with another 13 missing, authorities said on Tuesday.
Vehicles were swept away and disaster officials said farmland, key highways and bridges were inundated in the capital, Seoul.
President Moon Jae-in was set to hold an emergency meeting today, after he had urged national and regional authorities to "make all-out efforts to prevent further loss of life" the previous day, Reuters reported.
