"The death toll is now 130 people. We do not know the total number of homeless people at the moment, but counting is ongoing," Alain Mukuralinda, deputy government spokesperson, told AFP.
"What we know is that over 5,100 homes were destroyed and they all had families living in them."
Another 2,500 homes have been partially damaged, according to a government tally.
Mukuralinda said 77 people were hurt in the disaster, including 36 who are still in hospital with serious injuries.
Rivers of mud swept away homes and other infrastructure and cut off roads in several parts of the country, particularly the Western Province bordering Lake Kivu where the worst devastation was reported.
"I found my child buried under rocks and bricks that fell on him during the heavy rains. He died at the hospital," Anonciata, who only gave one name, told AFP in the hard-hit district of Karongi.
"It is very devastating for our family. One of my other children also got badly injured on the head. I pray he survives."
In Rubavu, another district badly affected, survivors were counting their blessings while coming to grips with the scale of destruction.
Jacqueline Mukamana rushed out of her home at midnight when neighbors alerted her that the river was flooding only for her home to be swept away.
"Our house, and everything (else), has been destroyed," she said.
Another resident, Paul Bizimana, was grateful he managed to get his family out: "I managed to rescue my kids and family members... at least they are safe."
The government was racing emergency supplies to the worst hit areas, where evacuees are sheltering in tents.
They have been advised to remain there until the rain stops, with fear of further mudslides and flooding with rivers still raging and land unstable.
Prime Minister Edouard Ngirente is expected to tour the worst-affected regions on Thursday.
The government will extend compensation of 100,000 Rwandan francs ($110) to each family for every relative killed in the disaster.
In May 2020, at least 65 people died in Rwanda as heavy rains pounded the region while more than 200 people died in floods and landslides in the first four months of 2018.
Experts say extreme weather events are happening with increased frequency and intensity due to climate change - and Africa, which contributes the least to global warming, is bearing the brunt.