Chinese Vice-Premier Hui Liangyu said on Tuesday the death toll of the 8.0-magnitude earthquake in the southwestern Sichuan Province is estimated to exceed 80,000.
Hui's statement was the first official acknowledgement that many of those still listed as missing might have perished.
The death toll stood at 69,181 as of noon on Monday, with 374,171 injured and 18,498 listed as missing, Hui said in a report on relief and reconstruction at the opening of the third session of the Standing Committee of the 11th National People's Congress.
"Quite a large number of those missing may have died," he said.
"The May 12 earthquake in Wenchuan County was the most destructive earthquake , one that affected the widest area and one posing the biggest challenge to rescue operations, since the founding of the People's Republic of China in 1949."
He admitted the disaster-relief work had been arduous.
Hui said the earthquake affected 417 counties, 4,656 townships and 47,789 villages, with a total disaster zone of 440,000 square kilometers.
The number of people affected was 46.24 million.
Since the main quake, 13,685 aftershocks had been detected, with five measuring above 6.0 on the Richter scale, 28 ranging from 5.0 to 5.9 and 189 from 4.0 to 4.9.
He said the relief work was difficult because most of the worst-hit areas were in mountains or deep valleys. The destruction of roads and communication links also prevented rescue staff and facilities from getting into the quake zone quickly.
He noted 7.79 million houses collapsed, with another 24.59 million damaged. The county seat of Beichuan and Yingxiu Township were almost leveled, he noted.
Infrastructure was also severely damaged. The quake cut off 16 major arteries and six railways and paralyzed power supply, telecom and water supply in large areas, he said.
Secondary disasters caused further damage, with landslides and mud-rock flows frequently striking the zone. Quake-triggered landslides blocked rivers and formed 35 quake lakes, with dangers of various degrees reported in 2,473 reservoirs.
The operation of 6,443 enterprises had ceased or been suspended after the quake, and 44.62 million head of livestock and poultry died, he added.
The government had done its utmost for survivors, and those affected by the quake had been provided with temporary shelters and the necessities of life.
Social order in the quake zone had maintained overall stability and quake-relief work had achieved "initial victory," he said.
Hui also remarked on the progress of the relief work, saying the country had sent more than 140,000 members of the People's Liberation Army (PLA) and armed police to help.
More than 100,000 public security staff, firefighters, paramilitary members and reservists had been dispatched to the quake zone, he added.
As of Monday, more than 1.46 million survivors had been transferred and 84,017 quake survivors were saved from the debris, he said, adding more than 96,800 medical staff had treated more than 2 million injured people as of Monday.
Infrastructure had been repaired and restored in the quake-devastated regions, Hui said.
Quake-relief personnel have broken through blocked major roads and rail lines, and power and water supplies have basically been restored in urban and rural areas.
No epidemics or mass food poisoning cases had been reported in the area due to prompt sanitation measures, he said.
Hui said sheltering of the quake survivors, prevention of epidemics and secondary disasters still remained prominent problems.