The World Health Organization on Tuesday warned the Covid pandemic was still volatile, saying there could be further trouble before the virus settles into a predictable pattern.

In the last 28 days, more than 23,000 deaths and three million new cases have been reported to the WHO, in the context of much-reduced testing.

While the numbers are decreasing, "that's still a lot of people dying and that's still a lot of people getting sick", WHO emergencies director Michael Ryan told a press conference.

He said respiratory viruses do not pass from a pandemic to an endemic phase, but instead move to low levels of activity with potentially seasonal epidemic peaks.