Zimbabwe's opposition party claimed an overwhelming victory against President Robert Mugabe in Saturday's presidential election, saying that the flow of results showed its candidate, Morgan Tsvangirai, had "massacred" the ruling Zanu-PF party.

The Movement for Democratic Change (MDC) defied a government ban on pre-empting the official announcement of the election results and released the count from polling stations that showed Tsvangirai beating the man who has ruled Zimbabwe for 28 years, even in the president's home territory of Mashonaland.

"We've won this election," said Tendai Biti, the MDC's secretary-general. "The results coming in show that in our traditional strongholds we are massacring them. In Mugabe's traditional strongholds they are doing very badly. There is no way Mugabe can claim victory unless it is through fraud. He has lost this election."

The government's electoral commission has yet to release the counts formally, but the MDC said that declarations posted at polling stations across Zimbabwe last night, and gathered from its agents observing the counts, showed Tsvangirai ahead of Mugabe in every province where results were available. The most dramatic gap was in Mashonaland West, where the MDC candidate had 88 per cent of the vote to the president's 12 per cent.