Exiled former Cabinet Minister Walter Mzembi believes President Emmerson Mnangagwa should have been invited for a photo-opportunity with King Charles III and state leaders of Commonwealth nations, as a guest.

Social media was ablaze after the portrait was shared online.

Mnangagwa's absence where his Zambian counterpart Hakainde Hichilema and Rwandese Paul Kagame stood shoulder to shoulder with King Charles III was interpreted as a clear snub.

Mzembi, who fled Zimbabwe at the height of the November 2017 coup before making a brief return said the snub was undiplomatic.

He was posting on Twitter from South Africa where he has remained holed up in fear of Mnangagwa and his military backed regime.

"The exclusion of Emmerson Mnangagwa whose country has applied for readmission to the Commonwealth was an undiplomatic gesture. In proper International Relations he would have been invited as a guest although not participating in discussions," said Mzembi.

Zimbabwe's application for readmission is currently under review, with Commonwealth members and the British government maintaining it lacks reform.

The British Parliament has gone as far as arguing he has not changed anything from his predecessor Robert Mugabe.

Added Mzembi: "Strategy Rooms must go ablaze with Reviews and Accountability Sessions on why there was a rebuff on Mnangagwa in London as if he was set up for embarrassment. Who slept on the job? Pretending all was well is the epitome of bureaucratic deception."

Mnangagwa did meet Commonwealth Secretary General Patricia Scotland, former British Prime Minister Tony Blair and UK's Minister for Africa Andrew Mitch.