The central city where the virus first appeared in humans late last year added another 1,290 victims on top of the 2,579 previously counted as of Thursday, reflecting incorrect reporting, delays and omissions, CCTV reported.
The revisions follow widespread speculation that Wuhan's death toll was significantly higher than reported, rumours fuelled by images of long queues of family members waiting to collect ashes of victims and reports of thousands of empty urns stacked at a single funeral home.
"In the early stage, due to limited hospital capacity and the shortage of medical staff, a few medical institutions failed to connect with local disease control and prevention systems in a timely manner, which resulted in delayed reporting of confirmed cases and some failures to count patients accurately," state broadcaster CGTN quoted an unidentified Wuhan official as saying.
Suspicion that China has not been transparent about the outbreak has risen in recent days, with U.S. President Donald Trump on Wednesday expressing skepticism about the country's previously declared death toll of about 3,000.
“Do you really believe those numbers in this vast country called China, and that they have a certain number of cases and a certain number of deaths; does anybody really believe that?” he said.
Some experts however believe fatality numbers in many other countries undercount the real death toll due to people who have died from COVID-19 without being tested or presenting at hospitals.
The number of total cases in Wuhan, a city of 11 million people, was revised up by 325, taking the total to 50,333 or about 60% of mainland China's total.
Doctors and government officials in Wuhan have been repeatedly questioned about the accuracy of the death toll by journalists on government-arranged trips.
Some of those officials acknowledged that people may have died without being counted in the chaotic early days of the outbreak, before testing was widely available.
"There couldn’t have been many because that was a very short period," Wang Xinghuan, head of one of two field hospitals built for the outbreak, told reporters in Wuhan on April 12. He stressed that he was not speaking for the government.
Before the revised Wuhan numbers were released, China said it had recorded 26 new cases of the coronavirus in the mainland on Thursday, down from 46 cases a day earlier, according to the National Health Commission.
It brought the total number of cases in mainland China to 82,367.
Of the new cases, 15 were imported infections, the lowest since March 17. The remaining 11 confirmed cases were locally transmitted infections, down from 12 a day earlier. The number of new asymptomatic cases increased to 66 from 64 a day earlier.
China does not include patients with no clinical symptoms such as a cough or a fever in its tally of confirmed cases.
No new deaths were reported.