The cost to rebuild Nepal, where the most devastating earthquake in eight decades demolished buildings, damaged roads and claimed thousands of lives, will exceed $10bn (£6.56bn, €9.16bn), according to finance minister Ram S Mahat.
The death toll has already exceeded 4,300 and could climb beyond 6,000, Mahat told Bloomberg on 28 April.
The government is struggling to save people who may be trapped, he said.
The reconstruction figure will be equivalent to about half of Nepal's $20bn economy, which is smaller than all 50 US states. An exact estimate is difficult to calculate, and Kathmandu will appeal to the world for help, Mahat added.
Mahat said: "We have reason to believe that there are survivors in the rubble but we don't have equipment to deal with the situation.
"In Kathmandu Valley itself, big buildings have collapsed and they don't know how to get people out. There is lack of adequate equipment.
"The cost is incalculable. It will be billions and billions of dollars in reconstruction and restoration of infrastructure. It will take years."
Earlier, Nepal's Prime Minister Sushil Koirala said the death toll could touch 10,000, while the UN has said eight million could be directly affected by the devastation.
On 27 April, Rajiv Biswas, chief economist, Asia-Pacific at IHS, pegged the total long-term cost of reconstruction in Nepal "using appropriate building standards for regions vulnerable to severe earthquakes" at over $5bn.
The true extent of the catastrophe will emerge gradually because an assessment of damage in rural Nepal has been hampered by extensive damage to infrastructure and widespread disruption to communications.