Monday was the 13th day since the flooding which killed more than 1300 people in Nepal and Tibet and left some 5000 missing, including foreigners, according to Nepal's disaster management agency.
In predominantly Hindu Nepal, mourning periods last 13 days, during which time close family members stay home and relatives visit to pay their respects.
Rituals are held on the final day to pray for the souls of the departed.
Several people whose relatives remain missing performed symbolic funerals on Monday.
Cremation is an important final rite in Hindu tradition, and performing the ceremony even without the bodies of their loved ones provided some families a sense of spiritual release.
The government had declared Monday an official day of mourning and ordered flags at government offices lowered to half-mast.
Search efforts continue for the missing, but some observers protested that not enough was being done.
In the capital Kathmandu, relatives gathered near the offices of the prime minister and key ministries to demand the government speed up search and rescue efforts for hundreds of people who had been working at hydropower plants and were either swept away by the rushing Bhotekhoshi River or buried under debris.
Sumana Shrestha stood with family members holding a poster with the photo of her 55-year-old husband, who has not been heard from since the day of the flood.
A consulting geologist, her husband had promised to return home after his shift at the project office for the Trishuli hydropower plant on the day of the flood. The two-and-a-half-storey building was completely buried by debris.
"We are here because we have not heard of any rescue attempt on this project, but it has been 13 days already," she said.
"The only thing we have been able to do is pray to God and hope for a miracle."
Another protester, Mahesh Prasad Shrestha, held a photograph of his brother Niraj Shrestha, a 52-year-old engineer who worked at the same site.
He said authorities only sent a small excavator by helicopter on the sixth or seventh day after the disaster.
"They should have ordered big helicopters from places like China or India to fly in equipment," he said.
Candlelight vigils were held in several places in Kathmandu in memory of the people who lost their lives during the flooding.
Rescue efforts have focused on 12 hydropower projects, where about 900 workers are missing and roughly 500 are believed to be trapped in various tunnels, authorities said.
Specialised rescue teams from India, China, South Korea and the United States have been searching through debris, damaged structures and tunnels at the projects.
Two Nepalese workers were rescued from one hydropower tunnel on Friday, while rescuers pulled out a Chinese man from the facility on Saturday.
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