KATHMANDU — The cost to rebuild Nepal after its most devastating earthquake in eight decades will exceed $10 billion and take years, Finance Minister Ram Mahat said.

Right now the government is struggling to save those who may still be trapped after the 7.8 magnitude temblor struck the Himalayan nation. The death toll has already exceeded 4,300 and could climb beyond 6,000, Mahat said in an interview on Tuesday.

“We have reason to believe that there are survivors in the rubble but we don’t have equipment to deal with the situation,” Mahat said at his office here in the capital. “In Kathmandu Valley itself, big buildings have collapsed and they don’t know how to get people out.”

His reconstruction estimate is equivalent to about half of Nepal’s $20 billion economy. The government will appeal to the world for help when the immediate rescue effort ends, Mahat said, adding that a precise figure is very difficult to determine.

“The cost is incalculable,” he said. “It will be billions and billions of dollars in reconstruction and restoration of infrastructure.”

Heavy rains in Kathmandu on Tuesday impeded efforts to find any remaining survivors. About a third of Nepal’s 28 million people have been affected by the quake, with about 1.4 million in need of food assistance in Asia’s second-poorest country.

“Due to the mountainous geography, infrastructure damage, collapsed bridges and damaged roads, access to many of the affected areas is reported to be extremely limited,” the United Nations said in a statement.