U.S. Secretary of State Hillary Clinton arrived in Angola on Sunday in a bid to bolster opportunities for U.S. business in the major oil producer.

Officials traveling with Clinton said the United States wanted to strengthen relations with Angola, from which the United States imports 7 percent of its oil and which rivals Nigeria as Africa's biggest oil producer.

Billions of dollars have been invested by major oil companies Chevron and Exxon Mobil in recent years to increase production in Angola -- both firms pump over half of the country's daily oil production.

A U.S. official dismissed suggestions Washington was concerned by the growing influence of China in Africa, where Beijing has displaced many Western countries with the weight of its investments.

The mention of our colleagues from Asia is a Cold War paradigm, not a reflection of where we are today, said the official.

Clinton is expected to hold a news conference at around 7:30 a.m. EDT (1130 GMT) before meeting Angola's oil minister.

BUSH ERA

Africa experts say Clinton will try to improve a relationship that ebbed during George W. Bush's administration.

They (Angola) jumped in bed with the Chinese and the U.S. stopped paying attention to them, said Stephen Morrison of the Center for Strategic and International Studies, a Washington think-tank.

Clinton also plans to focus on food security issues, with a push to get Luanda to diversify from focusing only on oil to a greater emphasis on agriculture.

Washington believes agriculture is a way to lift millions out of poverty in Africa. U.S.-based Dole Food Co. and Chiquita Brands International have been in talks with local authorities to invest in the banana industry.

Angola's main opposition UNITA party, which the U.S. helped bankroll in its fight against the government during the 1975-2002 civil war, urged Clinton not to shy away from issues like corruption, poverty and democracy when she meets President Jose Eduardo dos Santos on Monday.

Corruption and good governance has been a theme of Clinton's trip to Africa, echoing U.S. President Barack Obama when he visited Ghana last month.

UNITA accuses dos Santos of purposely delaying a presidential election, initially scheduled for 2009, to extend his three-decade rule.

It also says the president and the ruling MPLA party have kept a tight grip on the country's oil wealth while millions of Angolans remain poor.

We ask Clinton to be honest with the Angolan government and the truth is there is very little transparency when it comes to managing Angola's oil wealth, UNITA spokesman Alcides Sakala told Reuters.

(Editing by Robert Woodward)