The Chinese city of Wuhan, the original epicentre of the coronavirus outbreak, has revised the number of its virus-related fatalities up by 1290 to 3869, local authorities say.

The government of Hubei province, home to Wuhan, said on Friday that the number of casualties had been revised up by half due to late reports from medical institutions and because some coronavirus patients died at home while hospitals were overloaded in the early stages of the epidemic.

Wuhan’s Epidemic Prevention and Control Centre said it had also revised the total number of confirmed coronavirus cases in the city – where the virus was first reported in December 2019 – up by 325 to 50,333.

• See a real-time worldwide tally of coronavirus deaths here

The revision comes as the accuracy of China’s coronavirus data continues to be questioned abroad and by its own citizens.

The country’s official overall death toll remains below 5000. Other hard-hit countries already have much higher tolls – the United States has nearly 35,000 deaths from 675,000 cases, and Britain has nearly 14,000 deaths from more than 100,000 cases.

At the peak of the coronavirus epidemic in China in early 2020, the country’s hospitals were overloaded with patients, and health workers were overstretched, leading to delays and errors in reporting cases, the Wuhan centre said.

The outbreak appears to be largely contained in China. However, restrictive measures – including a border entry ban and temperature testing – remain in place.

• Wuhan lockdown lifted as Chinese case numbers fall

The revision of the official data is likely to fuel speculation about the accuracy of China’s figures – which have been questioned by US President Donald Trump. American intelligence officials believe China has concealed the extent of its coronavirus outbreak and under-reported cases and deaths.

Britain’s Telegraph newspaper reports that pictures of thousands of ash urns being ferried to funeral homes in Wuhan circulated on Chinese social media platforms in March, raising concern that the real number of deaths in Wuhan were higher than officially acknowledged.

China has denied intentionally under-reporting its coronavirus cases. But has also previously revised the data.

• China agrees to be more transparent as international tolls grow

Also on Friday, Home Affairs Minister Peter Dutton called for a rethink of Australia’s relationship with China following the pandemic. He said China must come clean about the origin of the virus outbreak – and families of the 65 people who have died in Australia deserved to know more.

“I think it is incumbent upon China to answer those questions and provide the information so that people can have clarity about exactly what happened,” Mr Dutton told the Nine network.

-with agencies