The slip happened in the early hours of Saturday morning and apart from the 12 victims, it also buried 13 houses and food gardens.
According to NBC News reporter Stanley Pil, who was at the site of the slip, authorities have moved in and are conducting search and rescue in the area.
The bodies are now at the Mt Hagen Hospital mortuary while the search is continues for the other two.
The slip engulfed Lamindi Village in Tendepo Ward Two. Speaking to RNZ Pacific around 11am local time the Tambul-Nebilyer district administrator Phillip Talpa said the community is still in a state of shock.
"We have not done any excavation or anything like that yet we are trying to mobilise resources to do excavation to find out who is actually buried underground," Talpa said.
Talpa said that the district had been subject to heavy rainfalls recently and there was a high risk of more slips occurring in the area. Others living in the area were been asked to move away.
"It just caught people off guard and it has really traumatised the people," Talpa said.