As widely expected, President Paul Biya, Cameroon’s ruler for the last 22 years, has won re-election for another seven-year term in office with an overwhelming 75 % of the vote, according to unofficial results announced by the interior minister.

Biya's main challenger, Opposition leader John Fru Ndi, came in second with 17 per cent, while another Opposition candidate, Adamou Ndam Njoya, garnered 4 per cent, interior minister Marafa Hamidou Yaya said in a statement broadcast on state television.

The Opposition vigorously protested the results, however, saying Monday's vote was marred by irregularities and fraud.

Yaya said the results were based on votes counted from most of the country's 23,000 polling stations. Votes from 43 polling stations in the southwest have yet to be tallied, he said.

A Constitutional Council, consisting of 11 Supreme Court judges appointed by Biya, is supposed to issue final, official results within two weeks.

Thirteen candidates were vying for the presidency. Opposition candidates disputed the results and repeated calls to annul the vote.

Njoya called the poll a "masquerade." Ndi said the election had been characterised by "widespread fraud," adding that "several persons voted more than once, ballot boxes were stuffed will ballot papers, our observers were beaten and driven from polling stations in almost all parts of the country."