Mugabe - who has led Zimbabwe consistently, first as prime minister and now as president - attended a lunch for children on Sunday at Harare's sports centre, and honoured popular sports heroes and establishment figures.

On Monday, he was expected to give a lengthy speech extolling Zimbabwe's achievements before a list of guests including the presidents of Botswana, Malawi, Namibia, Tanzania and the Democratic Republic of Congo.

But as red carpets were rolled out in preparation for the African presidents' arrival, Zimbabwe's opposition leader Morgan Tsvangirai called on his supporters to resist Mugabe's rule, saying: "The people are even more embattled than before April 18, 1980."

Mugabe was expected to deliver a speech on Monday that hails Zimbabwe's progress since Britain's Prince Charles witnessed the lowering of the Union Jack and the raising of Zimbabwe's black, red, green and gold striped flag.

Tsvangirai said, however, that independence celebrations underlined the country's economic and social poverty, and called for Zimbabwe's 15 million people, including 3.6 million now living abroad, to struggle against Mugabe's power.

"The 25 years merely registered a period of sustained economic decline.

"We have nothing to show for it except overwhelming poverty, a systematic loss of our basic freedoms and a national crisis ... the forces of democracy are under siege," the leader of the Movement for Democratic Change said.

"Only sustained democratic resistance and political pressure shall bring in the desired results," he said.

"In the history of democratic struggles, it is clear that perseverance pays in the end."

Tsvangirai criticised Zimbabwe's flawed elections, saying they had left the country at the mercy of "a determined tyrannical class ... a vampire and criminal clique". Mugabe and his party claimed victory in 78 of 120 elected seats in the parliamentary vote weeks ago, after which Mugabe nominated 30 more legislators, giving his party a two-thirds majority needed to amend the constitution at will. An editorial in the state-run newspaper The Sunday Mail, which was seen as a preview to Mugabe's address on Monday, listed the election as one of the country's main achievements and evidence of the "maturing of democracy".

The Sunday Mail also lauded Zimbabwe's redistribution of 5 000 white-owned farms, widely seen internationally as having contributed to the country's declining agriculture and escalating poverty.

Most of the more profitable farms went to Mugabe's supporters, military officers and party insiders.

The newspaper said, however, that the redistribution of white-owned commercial farms - accounting for 17% of Zimbabwe's farmland - was "a dream come true for the masses".

Discontent with Mugabe's rule has been mounting in recent years, as the president cracks down on dissent and media freedom. The independently owned Sunday Standard asked: "What is there to celebrate?" noting 80% unemployment, loss of food self-sufficiency and runaway inflation.

"A whole nation has been pauperised," it said. An ecumenical group, Christians Together for Justice and Peace, issued a statement supporting the warning of Roman Catholic Archbishop Pius Ncube, who feared rigged elections would lead to a possible "mass uprising" against Mugabe's rule.