Johannesburg - Britain's Princes William, 26, and Harry, 24, started a 1,700-kilometre rally in aid of charity through South Africa Saturday.

The two set off from Port Edward on the east coast of the country with some 80 others in the early morning sunshine on the eight-day Enduro Africa 2008 trek.

Each participant paid 1,500 pounds (2,600 dollars) to take part in the event, raising 300,000 pounds for charities such as Harry's Sentebale (don't forget me), founded in 2006, which helps AIDS orphans in the mountainous kingdom of Lesotho.

Others charities to benefit from the funds are the UN children's charity UNICEF and the Nelson Mandela Children's Fund.

The bikers plan to travel in groups of 10 across the South African wilderness, using dirt roads and steep goat tracks, and spending the nights in tents.

The route of the trek is renowned for its beautiful landscapes, but goes through one of the poorest regions of the country.

The roads are considered dangerous by South African drivers because of the many potholes.

Harry is a frequent visitor to the area as the parents of his South African girlfriend, Chelsy Davy, 22, own a luxury holiday flat in the port city of Durban, some 120 kilometres from Port Edward. (dpa)