The Democratic Republic of the Congo is gearing up for its first contested elections in 40 years on July 30, amid violent demonstrations by opponents of President Joseph Kabila and a threat by the country's Catholic bishops to reject any tainted result.

Thousands of protesters clashed this week with police in the capital, Kinshasa, after Catholic leaders complained about irregularities intended to boost Kabila in the registration of 25 million Congolese. Half of the nation of 60 million is Catholic.

“The climate in which the election is taking place is very tense,” said Jason Stearns, author of a report on the election by the Brussels-based International Crisis Group. “You will have winners and losers, and a lot of people think the institutional organisations have a strong bias toward the incumbent.”

The election is being closely watched by companies such as Phelps Dodge Corp., Nikanor Plc and Celtel International BV to see whether Congo can make a break from its war-scarred past. They are eager to invest in a country the size of Western Europe that is rich in copper, cobalt, uranium and other minerals, and poor in infrastructure such as paved roads and phone service.

Congo's Catholic bishops decided against urging a boycott of the elections and in a statement yesterday said they “reserve the right to determine the validity of the vote after careful reports of the accredited observers”.

All Catholics should “massively participate” in the elections, the bishops said. Kabila, the 34-year-old president of the transitional government that has ruled the nation since 2001, and his People's Party for Reconstruction and Development are likely to win the election, according to the Eurasia Group, a New York-based firm that analyses political risk for businesses.

“The market view is that Kabila will win, although no one expects much to change or a return to the chaos of the late 1990s,” Sebastian Spio-Garbrah, the firm's African analyst, said. “The danger is that the election turns out to be violent, the main opposition parties refuse to recognize the outcome and you have parts of the country with festering conflicts.”

Voters will cast ballots for president and the 500-seat National Assembly.

Stearns said Kabila has used his presidential guard, a force of about 15 000 separate from the army, to intimidate rival candidates, and money from the state-run diamond company to outspend them. His principal rivals are vice presidents Jean-Pierre Bemba of the Movement of Liberation of the Congo, and Azarias Ruberwa, a former Rwanda-backed rebel.

The former Belgian colony, once known as Zaire, is still recovering from a war that followed the 1997 ouster of dictator Mobutu Sese Seko. Ethnic Hutu killers responsible for the genocide in Rwanda took refuge in eastern Congo and started the conflict, which drew in five other nations. The fighting, along with starvation and diseases that spread because of it, killed more than 4 million people.

Eastern Congo remains plagued by armed groups supported by Rwanda and Uganda. The United Nations, which has 17 000 peacekeeping troops in Congo in the largest of its 18 missions, last month added another 1 500 European troops to secure the country. The UN is spending $1,1-billion a year on its military mission in Congo.

The UN's 2 000 workers in the nation trained 300 000 Congolese to manage 9 000 voting sites. The total cost of the election could reach $500-million, according to Ross Mountain, deputy head of the UN peacekeeping mission.

More than 1,200 international observers will monitor the voting, from groups including the European Union, the African Union, the Development Community of Southern Africa and the Carter Center in Atlanta, headed by former US President Jimmy Carter. Jendayi Frazer, US assistant secretary of state for Africa, is leading an observation team to Congo to help ensure the elections “complete the transition from war to peace,” the State Department said.

The African Union issued a statement last week saying conditions for a fair election had been met.

“It is vital for the country's future that these elections, which are a symbol of hope for the whole of Africa, should be credible and transparent,” UN Secretary-General Kofi Annan said. “History will pass a severe judgment on anyone who tries to disrupt or otherwise undermine the elections.”

Ileka Atoki, Congo's UN envoy, said companies are “lining up” to extract the nation's untapped gold, zinc, tin, nickel, uranium, oil and timber reserves, as well cobalt -- it has two- thirds of the world's reserves -- and industrial diamonds.

Celtel, a Hoofddorp, Netherlands mobile-phone company, aims to double its 1,3 million customers in Congo; Nikanor, based in the Isle of Man in the UK, raised $400-million this month for mining, and Phelps Dodge, headquartered in Phoenix, is developing a 600-square-mile concession to extract copper and cobalt.

While Kabila's government said the economy is expected to expand by 6,5 percent this year, its per-capita economic output ranks 227th out of 232 nations on a US Central Intelligence Agency list.

Kabila and his party should dominate voting in eastern Congo provinces that form his home base and have 12 million registered voters, according to Stearns. Kabila is credited there with unifying the country and driving out many of the Rwandan and Ugandan invaders, Stearns said.

“There has been very little intelligent debate,” Stearns said. “Most of the candidates seem like carbon copies in their statements that they'll bring in more investment and fight corruption. The decision will be made on personalities, some ridiculous promises and stunts like sprinkling money from helicopters.”

A recent poll put Kabila at about 35 percent -- short of the 50 percent needed to avoid an October runoff. Bemba's use of his radio and television stations could land him in second place. Ruberwa and his party could play a spoiler role after the election, Stearns said.

Another threat to the credibility of the election, as well as the outcome, is posed by Etienne Tshisekedi's Union for Democracy and Social Progress. It decided to boycott the voting, then reversed its position too late to register. Tshisekedi's faction controls much of northern Katanga province, which Spio-Garbrah called the “prize jewel” of Congo because of its copper and uranium deposits.

The key will be whether Kabila can hold together some of the people he has worked with in the transitional government,” Chester Crocker, a professor at Washington's Georgetown University and a former assistant US secretary of state for African affairs, said in an interview. “He hasn't been fully tested yet, and this is a big opportunity, a moment when the Congolese people could overcome amazing obstacles, or we could see the world disengage again.”