Zimbabwean President Robert Mugabe on Saturday celebrated his 91st birthday with a lavish million-dollar bash that was slammed by the opposition as "obscene" in a country wracked by poverty.

Thousands of supporters of the ruling ZANU-PF, many wearing party regalia emblazoned with the president's image, sang and danced as he arrived for the jamboree at a luxury hotel in the famed Victoria Falls resort.

Assisted by his wife Grace, the elderly liberation leader, who wore a black suit, white shirt and red tie, threw 91 balloons into the air.

The party, which comes a week after Mugabe's birthday, was held on the hotel golf course, with white marquees housing the guests.

Elephants were slaughtered for the feast and seven huge cakes were on display in one of the tents.

One giant 91-kilo creation depicted the spectacular Victoria Falls, which empty into the Zambezi river that forms the border between Zimbabwe and Zambia.

The extravagance of Mugabe's birthday parties are a subject of annual controversy in Zimbabwe.

The opposition Movement for Democratic Change called Saturday's festivities "obscene".

"All the money that has been collected to bankroll this obscene jamboree should be immediately channelled towards rehabilitating the collapsed public hospitals, clinics and rural schools in Matebeleland North province," MDC spokesman Obert Gutu said last week, referring to the province where Victoria Falls is located.

Mugabe, who has ruled Zimbabwe since independence from Britain in 1980, is the world's oldest leader.

One of the banners welcoming him to the party praised him as "the icon of Zimbabwe's revolution."

"Forward with President Mugabe," supporters chanted.

Several speakers wished him good health, with one youth leader urging the authorities to declare February 21 – his birthday – a national holiday.

While hailed by many African peers as a liberation hero, critics accuse the Zimbabwean strongman of turning southern Africa's former bread basket into a basket case by trampling human rights, democracy and the rule of law.

Mugabe's violent seizure of white-owned farms triggered food shortages and hyper-inflation, while Europe and the United States imposed sanctions on Zimbabwe over elections seen as rigged.

In an interview marking his birthday, Mugabe admitted he blundered by giving ill-equipped black farmers vast tracts of farmland under his controversial land reforms.

"I think the farms we gave to people are too large. They can't manage them," Mugabe said.

He also shrugged off questions over an incident earlier this month in which he missed a step and stumbled from a podium.

"I have yet to come across to a person who has not fallen. It was a slight fall, missing a step," Mugabe told state-controlled television.