WASHINGTON (REUTERS) - President Barack Obama on Thursday will name top international economic affairs adviser Mike Froman as his choice to be US Trade Representative (USTR), a White House official said, handing the job to a longtime friend who has played a big role in shaping trade policy for the past four years.

Mr Froman, if confirmed by the Senate, will take the reins as the top US trade ambassador in time to oversee the expected completion of a landmark free-trade agreement, the Trans-Pacific Partnership pact between the United States, Japan and 10 other countries.

The US and the 27 countries of the European Union are also preparing to launch talks on the proposed Transatlantic Trade and Investment Partnership, a free-trade agreement that will cover half of world economic output.

"The new USTR has both enormous opportunities and enormous challenges that have to be reckoned with," said Ms Charlene Barshefsky, who held the post in the late 1990s under former president Bill Clinton.

Mr Obama will make the announcement at 1400 GMT (10pm Singapore time), the official said.

Mr Froman, whose connection to Mr Obama goes back to their days on the Harvard Law Review, is already well known in diplomatic circles for his role in leading US preparations for more than a dozen international economic summit meetings.

He also oversees the administration's economic engagement with China, India, Brazil, Russia, Japan and the EU and the development of economic strategies for the Middle East and Africa.

The official said Mr Froman had been asked to play a continuing role at the White House on international economic issues.

By moving to USTR, the former Clinton administration official will be elevated to Cabinet status and focus his portfolio more narrowly on trade.

In addition to establishing trade rules for the 21st century through the two regional agreements, the US must develop better strategies to stop theft of corporate trade secrets and intellectual property that drive economic growth.

Mr Froman needs to "infuse the trade agenda in every aspect in the ways in which U.S. competitiveness can be enhanced and US innovation can be protected", Ms Barshefsky said.

The former Citigroup executive is widely respected by both Republicans and Democrats.

"Froman is a superb choice and will bring both energy and experience to the post... (It is) good news for all those wishing to see a more globally engaged United States," said Mr Dan Price, who was chief international economic affairs adviser for former president George W. Bush.

Ms Barshefsky, who like Mr Price spoke with Reuters in anticipation of an announcement, was equally enthusiastic.

"He knows the issues. He has a high degree of experience. He's exceptionally intelligent and obviously committed to a more open, equitable global economy," Ms Barshefsky said.

One of Froman's biggest challenges will be meeting the goal of finishing the Trans-Pacific Partnership talks by the end of the year. Japan recently joined the negotiations but will not actually participate formerly until the 18th round in July, increasing doubts of a deal this year.