So far troops have rescued 150 people from the worst-hit site in central Kegalle district, but hopes are fading for another 134 still unaccounted for.
No more people were found overnight, dead or alive - on Wednesday 14 bodies were pulled from the mud.
Five more bodies were found at the site of another mudslide in the district, bringing the death toll there to 10.
Landslides and flooding caused by days of torrential rain have hit many parts of the country, killing at least 43 people in total, according to official figures. Nearly 350,000 people have been displaced.
In the worst-hit area, Aranayake district, three villages were buried after a huge section of hillside sheared away in the rain on Tuesday.
Bad weather is hampering the army's efforts to reach possible survivors.
"I fear the missing 134 could be dead at this point," Maj Gen Sudantha Ranasinghe, the officer in charge, told BBC Sinhala. "But we will continue our operation to recover the bodies to give families some peace."
We started to climb up to the disaster site with troops who were going back on Thursday morning to continue to search for survivors. However they suspended their mission and evacuated the area along with us and some villagers who had returned.
Rain was beating down on the collapsed mountain again, creating a risk of further landslides.
We had to take shelter in a tiny schoolroom on higher ground. Villagers we spoke to were losing hope of finding any more survivors.
We waded through mud and silt to reach the foot of the mountain where most of the devastation has taken place. Army units have identified several places where people may have been buried in the landslide.
In one of the villages, Pallebage, local resident PG Sekara said: "The army keeps going up the mountain, but they're not going to find anything. To find survivors they will have to dig about 40 feet now."
Prema Adikari said she feared she had lost her brother and his family.
"My brother's house is completely destroyed. They were inside when the mudslide started. His 15-year-old daughter and his wife were also in the house,"  she told BBC Sinhala.
"When it rains, the canal waters nearby get so loud - they had not heard the neighbours warning. Only one member of the family remains, my nephew, who had gone to the shops nearby when the landslide struck. At least we want to see their bodies."
At Bulathkohupitiya, the site of the second, smaller landslide in Kegalle district, six people are still reported missing.
Sri Lanka's monsoon rains often bring floods but officials say these are the worst for several years.
Many displaced people have moved to shelters, and officials have appealed for water, dry food rations and sanitary items. Low-lying coastal areas have also been hit.
In southern India the authorities are on alert as the rains move up the country's east coast.
At least 280 people died in a month of heavy rains and floods in the city of Chennai and other parts of Tamil Nadu state last year. The rains, the heaviest there in a century, were blamed on climate change although city officials were also criticised for being unprepared.
Other parts of India have been suffering a severe drought in recent weeks.
Sri Lankan teams searching for scores of people missing after a landslide fear there may be no more survivors.