Cameroon's president is in "excellent" health, senior officials have insisted after a long public absence stoked widespread speculation about the 91-year-old leader's condition.

President Paul Biya has not been seen in public since 8 September, when he attended a China-Africa forum in Beijing.

He has since missed events he was scheduled to be at, such as the United Nations General Assembly in New York.

But in a statement, the head of Cameroon's civil cabinet said Biya was well and condemned the "mischievous individuals" speculating about the president's health and "eventual death".

The statement came after days of opposition parties and civil society groups calling for information on Biya's health and exact whereabouts.

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"The head of state continues to exercise his duties in Geneva and has never departed the [Swiss] city following his visit to Beijing," Samuel Mvondo Ayolo, director of the civil cabinet said on Wednesday evening.

Biya has long been criticised for the amount of time he spends outside the country - and in Switzerland in particular.

In 2018, the Organized Crime and Corruption Reporting Project (OCCRP) reported that since coming to power in 1982, Biya had spent the equivalent of four-and-a-half years on overseas trips.

The Intercontinental Hotel in Geneva is said to be his favourite destination.

In a separate statement, government spokesperson René Sadi said Biya would return to Cameroon "in the next few days".

He dismissed reports of Biya's ailing health as "pure fantasy".

After 42 years in power, Biya is one of Africa's longest-serving leaders.

Under his rule, Cameroon has moved from being a one-party state to multi-party politics, but it has also been marked by endemic corruption.

Democratic gains have also been reversed, leading to the abolition of presidential term limits in 2008.

Cameroon is also in the grips of a secessionist war that has killed more than 6,000 people in the west of the country.