The incident occurred as the cliff wall at a suspended jade mine near Kayin Chaung village in Hpakant collapsed, killing company staff and security personnel at 2 p.m. local time, the official from the township general administration department told Xinhua news agency.
So far, 13 bodies have been recovered and five are still missing, the department official added.
Rescuers were able to rescue two security personnel, who were later hospitalised.
Search by local authoritiesfor the missing was underway.
The tragedy occurred on Friday in the town of Paung, in Mon state, Efe news reported citing officials.
The landslide was caused by heavy rains that have plagued the region for days and forced around 38,000 people throughout the country to leave their homes, according to UN figures.
On Saturday, the Fire Department updated the number of victims in a statement and warned that the figure could increase during the ongoing search and rescue operation.
One of the survivors, a 70-year-old woman, told Efe on the phone that she lost 13 family members to the natural disaster, which she described as "unprecedented during her life".
"This is the very first time, I've never seen anything like this before in my life," she said.
Another survivor Ko Chan Aye lost 14 members of his family. He was saved because he was out shopping in another area when the landslide hit.
"I think there could have been more than a hundred people buried. I have no hope that many will remain alive," he said.
Hundreds of residents of nearby villages were left isolated and awaiting aid as heaps of mud blocked roads and paths.
Dozens of excavators and heavy machinery were deployed in attempts to find any survivors alive in the quagmire.
The landslide, which was caused by heavy flooding, took place on Friday in the town of Paung, Mon state, reports Efe news.
The Fire Services Department said that 48 bodies had been recovered and search-and-rescue efforts were underway to locate an undetermined number of missing people.
Dozens of bulldozers and heavy machinery have been deployed to find potential survivors in a race against time.
The operation is being overseen by ministers from the national government.
Witnesses told Efe that around 100 people could be buried under the rubble, though authorities have not confirmed that figure.
In addition, hundreds of residents of nearby villages have been left isolated while awaiting aid as roads have been destroyed and cut off by torrents of mud.
The intense monsoon rains have also forced the evacuation of nearly 38,000 people across the country, according to the UN.