Zimbabwe's veteran President Robert Mugabe on Saturday avoided the controversial subject of his future as he buried a senior political colleague and friend who had been pressing him to retire.



Mugabe, 92 and one of Africa's longest serving leaders, is eligible to seek re-election at the end of his current five-year term in 2018, but has increasingly looked frail, stoking a scramble in his ruling ZANU-PF party to succeed him.



In an hour-long speech on Saturday at the state funeral of Cephas Msipa, a former cabinet minister and ZANU-PF member, Mugabe, in power since independence from Britain in 1980, largely dwelt on his comrade's role in the 1960s-70s liberation struggle.



Msipa, regarded as one of Mugabe's closest friends, died aged 85 after retiring from government about 10 years ago. In recent years, he told media he had tried but failed to persuade Mugabe to step down.



"I feel sorry for him as a friend. He really needs a rest. It's good for him, good for his family and good for the party," Msipa said in a newspaper interview earlier this year.



Mugabe has never publicly commented on his friend's views.



But on Saturday he told thousands of mourners that "Msipa was always an honest man and he always spoke his mind fearlessly."



Splits have developed in Mugabe's ZANU-PF over who will take over from him, with one faction said to be maneuvering to impose his wife Grace as a possible successor against Vice President Emmerson Mnangagwa, a longtime political fixer who has the backing of war veterans.



In an unprecedented attack in July this year, the veterans of Zimbabwe's war against white minority rule called Mugabe a dictator, highlighting rising tension over the succession issue and mounting economic woes which critics blame on his mismanagement.



Political analysts say Mugabe has manipulated Zimbabwean politics to tighten his grip on power and set himself up as a president for life.



He is however facing increasing dissent, with opposition and social movements staging a series of protests in recent months.



With speculation also rising over his health, Mugabe has denied suffering from prostate cancer, and says his regular visits to Singapore are for routine medical checks and eyesight problems.



Analysts say Zimbabwe could suffer political instability if Mugabe dies in office before the matter of his successor is resolved.