Hundreds of troops have been using heavy equipment to dig through tonnes of mud that buried the tin-roofed homes of workers at a tea plantation.
It is still not clear how many people are trapped in the disaster which was caused by heavy rain.
The authorities have evacuated hundreds of people from nearby villages due to fears of fresh landslides.
Bad weather has been hampering rescue and recovery efforts.
"We are suspending the search operation because it is not safe to work in this rain," Maj Gen Mano Perera told journalists, AFP news agency reports. "We hope to start work tomorrow morning if the weather improves.
"There were no concrete structures which could have acted as air traps for victims to survive," he said, adding that no survivors or bodies had been found on Thursday.
Officials said on Wednesday that eight bodies had been recovered.
The deadly mudslide hit the Meeriyabedda tea plantation near the town of Haldummulla, about 200km (120 miles) east of the capital Colombo, on Wednesday morning. Part of a mountainside crashed into the tea estate, burying some of the workers' homes in 9m (30ft) of mud and debris.
An estimated 100 people are still listed as missing, the national Disaster Management Centre (DMC) says - locals say the figure is about 200.
Some of those originally classified as missing were subsequently discovered to be at work or in school. Correspondents say that compiling a definitive figure has been made harder because an office where village records were maintained was destroyed in the landslide.
Monsoon rains are caused by winds in the Indian Ocean and south Asia. They bring about wet and dry seasons in much of the region, and have a large impact on local ecosystems.
Are you, or do you know anyone, in the area? Email [email protected] with your stories.
Read the terms and conditions.