The World Health Organisation is reportedly convening an emergency meeting to discuss the alarming spread of the killer monkeypox virus around the world.

The United Nations' health authority is bringing together leading experts on the rare disease as a number of new countries announced their first confirmed cases on Friday, according to The Telegraph.

Eleven countries — including Australia, the US, Spain and Italy — have now detected monkeypox, in the first global outbreak of its kind.

In the UK, the number of cases of monkeypox doubled on Friday.

The main concern is how the virus — usually concentrated in West Africa — may be spreading, with many of the new cases detected in people who had not recently travelled to Africa.

The WHO will also be examining why clusters include gay and bisexual men, the paper said, with the US Centers for Disease Control and Prevention (CDC), and British and Australian authorities issuing similar warnings.