Chinese authorities reported nearly 60,000 Covid-related deaths at hospitals across the country since the end of strict pandemic restrictions in December, following criticism from groups including the World Health Organization for underrepresenting the severity of its outbreak.

Jiao Yahui, director of the medical affairs department for China’s National Health Commission, said there had been a total of 59,938 deaths related to Covid-19 infections at Chinese hospitals between December 8 and January 12, according to state media reports on Saturday.

“Owing to the relatively large amount of data and information, in order to reflect the mortality situation [for Covid-19] in China scientifically, objectively and realistically . . . we organised experts to conduct a systematic analysis of fatality cases, which took a long time,” Jiao said.

The publication of a sum total for Covid-related deaths at hospitals stops short of providing comprehensive mortality figures for the disease, after health officials narrowed the definition of Covid deaths and cases.

Beijing had reported limited fatality data since December 7, when Chinese authorities announced significant relaxations to President Xi Jinping’s “zero-Covid” pandemic policy, which had slowed economic growth.

The policy, which involved locking down many of China’s largest cities for months on end under strict quarantine, began to crumble last year as authorities struggled to contain more transmissible variants. The harsh restrictions also triggered a wave of nationwide protests in November.

Before the reversal Xi had characterised Covid-19 as a “devil virus” that could only be vanquished in an “all-out people’s war”.

Criticism of China’s mortality statistics had mounted in the weeks following the sudden policy shift, with only a few thousand Covid-related deaths reported by early January despite projections by experts of as many as 1mn deaths during the current wave.

Last week, in its strongest criticism of China’s pandemic policies to date, the WHO said it believed statistics released so far “underrepresent the true impact of the disease in terms of hospital admissions, in terms of ICU [intensive care unit] admissions, particularly in terms of deaths”.

Internal Chinese government estimates indicated that about 250mn people, or about a fifth of China’s population, may have been infected by late December.

The official figures released on Saturday by China’s NHC showed about 5,500 deaths from respiratory failure caused by Covid-19 infections, and another 54,400 deaths from infection combined with underlying health conditions.

The average age of fatalities was just over 80 years old, with more than 90 per cent of those who died aged 65 or over.