Zimbabwean President Robert Mugabe is in Singapore for a medical review after undergoing a cataract operation there last month but is expected to come home before his birthday next week, state media reported on Sunday.

Mugabe, one of Africa's longest serving leaders who turns 87 on February 21, last month dismissed as naked lies media reports that he had undergone an operation for a prostate problem in Malaysia.

The state-owned Sunday Mail said opticians in Singapore, where Mugabe spent a month-long holiday with his family from the end of December, had scheduled a review for the veteran leader.

He went for a review following a small medical procedure he underwent while on holiday, Mugabe's spokesman George Charamba told the paper. He had a cataract in his eye, so that was removed and he was asked to return by opticians.

A cataract is a clouding of the lens in the eye that affects sight, normally in older people, and can lead to blindness.

Mugabe told Reuters in an interview last September that he was surprised by constant speculation over his health but hardly paid any serious attention to it.

Mugabe has been in power since independence from Britain in 1980, but was forced to form a power-sharing government with his arch-rival, Prime Minister Morgan Tsvangirai, in February 2009 after a disputed re-election in 2008.

Mugabe's ZANU-PF party has nominated him as its candidate for presidential elections he wants to hold this year.

Tsvangirai's Movement for Democratic Change has urged Mugabe to drop his early election plan, saying the poll could lead to a bloodbath.

A dozen people have been injured in clashes between supporters of ZANU-PF and MDC in the past two weeks, and a ZANU-PF mob looted shops in the capital Harare last week.