"It will be a miracle if anyone is found alive," said Home Ministry spokesman Laxmi Dhakal. "But we have not completely given up yet and are continuing to look."
The death toll now stands at 6,621 people with an additional 14,566 others injured, according to Nepal's National Emergency Center.
The United Nations estimates that over 3 million people are in need of food assistance -- nearly half of those need it immediately.
Supplemental feeding is necessary for 200,000 children and pregnant or lactating women in the country. And therapeutic feeding in needed for some 15,000 children with severe acute malnutrition, and 70,000 more with moderate acute malnutrition.
Access remains a key obstacle, particularly outside the Kathmandu valley -- some villages can only be reached by helicopter, which are a limited. Debris management will be required for humanitarian supplies to reach remote areas.
Shelter is the most critical need, along with food and water. The UN estimates that half-a-million homes have been destroyed across the country. There is a desperate need for tents, tarpaulins and blankets. In some areas, there are reports of as many as 100 people sharing a single communal tent.
A total of $61 million in humanitarian pledges, commitments and contributions has been provided for earthquake response so far, according the UN's most recent situation report.
But much more is required.
The pace of assistance needs to be sped up in order to reach affected populations before the monsoon season starts, the report says.
On Friday, the UN's humanitarian affairs chief, Valerie Amos, joined with the European Union's Commissioner for Humanitarian Aid and Crisis Management, Christos Stylianides, to ask for $415 million for immediate humanitarian relief from the international community. Both Amos and Stylianides traveled to Nepal to help coordinate the humanitarian response.
"I am heartened and encouraged by the generosity and solidarity shown to date," Amos said in a statement. "But I am also conscious of the urgent need to provide emergency shelter and basic goods and services to people affected as the monsoon season approaches. So many people have lost everything."
UNICEF has also launched an appeal for $50 million to support its humanitarian response.
"The earthquake has caused unimaginable destruction," said Rownak Khan, the UNICEF deputy representative in Nepal. "Hospitals are overflowing, water is scarce, bodies are still buried under the rubble and people are still sleeping in the open. This is a perfect breeding ground for disease."