The director-general of the World Health Organisation (WHO) has asked for 675 million dollars (£520 million) to help countries address the expected spread of the new coronavirus that emerged in China.

Tedros Adhanom Ghebreyesus acknowledged that the sum is a lot, but said it is “much less than the bill we will face if we do not invest in preparedness now”.

Mr Tedros said that in the last 24 hours, the UN health agency has seen the biggest jump in cases since the start of the outbreak.

He also responded to published comments from John Mackenzie, a member of the WHO’s coronavirus emergency committee, that China’s initial response to the outbreak was “reprehensible” and that cases were not rapidly reported.

Mr Tedros said he would have expected higher numbers of cases if China had been hiding them.

“I don’t think it helps now,” he said of speculation about any mistakes in the early stages of the outbreak.

“Let’s take the action we can take today to prevent this outbreak from spreading all over the world.”