Britain's Queen Consort, Camilla, has tested positive for COVID-19, Buckingham Palace said on Monday.

The 75-year-old wife of King Charles III was said to be suffering from a “seasonal” illness, but a positive Covid test has led to all her engagements for the week now being cancelled.

“After suffering the symptoms of a cold, Her Majesty the Queen Consort has tested positive for the Covid virus," the Buckingham Palace statement said.

"With regret, she has therefore cancelled all her public engagements for this week and sends her sincere apologies to those who had been due to attend them,” the statement added.

The Queen was scheduled to carry out several engagements across the West Midlands region of England, including celebrating the centenary of Elmhurst Ballet School in Edgbaston, Birmingham.

She was also set to visit the Southwater One Library in Telford to thank staff and representatives from outreach and voluntary groups for their contribution to the community.

A Buckingham Palace spokesperson said it was hoped a new date could be found soon for the postponed events.

Camilla contracted Covid early last year and was forced to cancel her appearance at several events.

Charles also tested positive for the virus a few times over the past few years, with mild symptoms.