Zimbabwe's veteran leader Robert Mugabe will be sworn in for a new five-year term Thursday in a massive stadium inauguration that will be boycotted by his election rival. Opposition leader Morgan Tsvangirai insists the July 31 vote that returned the 89-year-old to power was rigged and will shun the swearing-in. The event will take place at the country's largest 60,000-seater sports stadium and around 40 leaders have been invited. "It's going to be a grand occasion, no doubt about that," said Simon Khaya-Moyo, chairman of Mugabe's ZANU-PF party. A constitutional court ruling confirmed Mugabe as president and declared the elections "free, fair and credible" and that the results "reflected the free will of the people of Zimbabwe." But Tsvangirai's spokesman said the opposition leader "can't attend a robber's party." "Expecting Tsvangirai to attend the inauguration is like expecting a victim of robbery to attend a party hosted by the robber," Tsvangirai's spokesman Luke Tamborinyoka told AFP. The inauguration had been delayed after Tsvangirai challenged the poll results in a petition to the constitutional court. "We are excited about the inauguration ceremony," Rugare Gumbo, spokesman for ZANU-PF, told AFP. "Our win represents the defeat of neo-colonialism and tomorrow we are celebrating not only President Mugabe's inauguration but the victory of Zimbabwe, Africa and progressive forces across the world." Unlike previous investitures which were low-key, the ceremony promises to be high-profile in what is seen as a show of power designed to confer legitimacy amid persistent questions around the vote which extended Mugabe's 33-year grip on power. The organisers said the event would be similar to Mugabe's inauguration as prime minister in 1980. But of the foreign leaders invited, only Namibia's Hifikepunye Pohamba is so far known to have confirmed. South Africa, which brokered a peace deal after the violence tinged 2008 vote, is sending Deputy President Kgalema Motlanthe. Botswana and Malawi will do the same. Former leaders from Tanzania, Botswana, Mozambique, Namibia and Zambia will attend. A music concert will include artists from South Africa, Zambia and Jamaica -- whose iconic Bob Marley played at Zimbabwe's independence event. "This inauguration is being projected as the crowning of a victory of a struggle for the past 13 years against big Western powers," said Eldred Masunungure, a political scientist from the University of Zimbabwe. There is however also an "unintended meaning," he said. "It can be read as a farewell event for Mugabe. It reminds one of Jesus's Last Supper." Thousands of Mugabe's supporters were expected to troop in from across the country. The electoral commission declared Mugabe winner with 61 percent of the vote, against Tsvangirai's 34. The elections ended a shaky power-sharing government formed by Mugabe and Tsvangirai four years ago to avoid a tip into conflict following a bloody presidential run-off election. Local observers have judged the elections flawed and Western powers have raised serious doubts over the vote. But regional and continental groupings the Southern African Development Community and the African Union were less critical. Tsvangirai condemned the election as "a farce" and "a massive fraud" and petitioned the court to overturn the result. Among a series of complaints, he queried the suspiciously high number of voters who were turned away from polling stations in urban areas which are considered opposition strongholds. He also charged that his party's supporters in rural areas were intimidated by Mugabe party backers into feigning illiteracy and voting in the presence of police and election officers. But in a surprise U-turn on Friday, Tsvangirai withdrew his petition saying he would not get a fair hearing. He said the courts had frustrated his efforts to access election materials he wanted to use as evidence. But the constitutional court went ahead and handed down a ruling on the case anyway. A vendor sells flags on a street in Harare on August 21, 2013, the eve of President Mugabe's inauguration ceremony. Zimbabwe's veteran leader Robert Mugabe will host a massive stadium-filling presidential inauguration to usher in a new five year term Thursday, despite expected limited attendance by foreign leaders and a boycott by his election rival. Mourners at the August 14 funeral of Morgan Tsvangirai supporter Rebecca Mafikeni, who died in custody. Zimbabwean opposition leader Tsvangirai will not attend President Robert Mugabe's inauguration Thursday, aides said, insisting the vote which handed the 89-year-old another five-year term was rigged. Zimbabwe's newly re-elected President Robert Mugabe speaks at a SADC summit in Lilongwe, on August 18, 2013. Veteran leader Mugabe will host a massive stadium-filling presidential inauguration to usher in a new five year term Thursday, despite expected limited attendance by foreign leaders and a boycott by his election rival.