The top Republican on the Senate Foreign Relations Committee said President Barack Obama is missing opportunities to strike closer ties with Brazil, allowing China to steal market share from U.S. companies in Latin America’s biggest economy.

In prepared remarks Senator Richard Lugar will deliver Friday in Washington, D.C., the Indiana Republican said the United States needs to elevate its relationship with Brazil to the status currently enjoyed by longstanding allies such as Canada, the United Kingdom and Australia.

“The U.S. agenda with Brazil should be much more ambitious,” according to Lugar’s speech to the Brazil-U.S. Business Council, an advanced copy of which was provided by his office. “We are missing important opportunities to advance our mutual interests.”

Brazil is helping anchor global economic growth as the country invests to host the 2014 soccer World Cup and 2016 Olympic Games, and as the state-run Petroleo Brasileiro SA develops the biggest offshore oil finds in the Americas in three decades. After expanding 7.5 percent in 2010, the central bank forecasts the $2.1 trillion Brazil economy will grow 3.5 percent this year.

While applauding Obama for making Brazil the centerpiece of his tour of Latin America earlier this year, Lugar said that more engagement is needed. A bilateral tax treaty — Brazil is the largest economy with which the U.S. lacks such an accord — and a market-access agreement with the Brazil and Argentina-led Mercosur trade bloc would help regain lost momentum, Lugar said.

“In too many cases, U.S. market share is being lost to China and other countries whose governments have moved more swiftly to embrace the opportunities of the Brazilian market,” Lugar said. “It’s critical to move now, not only because of competition from Asia and elsewhere, but because Brazil’s economic role in the hemisphere is expanding rapidly.”

National Security Council spokesman Tommy Vietor said Obama is committed to increasing U.S.-Brazil ties and that the U.S. was supporting Brazil’s desire to play a bigger role in organizations like the International Monetary Fund, World Bank and the Group of 20 nations.

Obama, speaking to a CEO business summit in Brasilia on March 19, said “It’s time for the United States to treat our engagement with Brazil on economic issues as seriously as we do with nations like China and India.´´

China overtook the U.S. as Brazil’s biggest trading partner in 2009 on stronger demand for the nation’s soybeans and iron ore. Still, exports of U.S. goods to Brazil have surged 22 percent so far this year, helping to pad a U.S. trade surplus with the country that stood at $9.7 billion through September.