Contentious legislation in the United States aimed at pressuring China to raise the value of the yuan reflects broader American frustrations with its trade partner, a senior U.S. trade official said on Tuesday.

The currency bill that was debated in the Senate last week represented the frustrations that many people feel about China not always working as a partner in creating a level playing field, said Francisco Sanchez, the U.S. Under Secretary of Commerce for International Trade.

It isn't just about currency, it's about intellectual property rights protection, access to government procurement opportunities, he told reporters during a visit to Hong Kong.

Democratic lawmakers vowed last week to press for a vote by the House of Representatives on a bill to punish China for keeping its currency undervalued, which they say gives Chinese companies a price advantage in global markets.

Although the Senate passed the measure, its fate in the House is uncertain. Republican legislators are opposed to the bill, and the Treasury Department said last Friday it would delay until later this year a ruling on whether China is manipulating its currency.

It is important for both China and the U.S. as trade partners to put those frustrations and concerns to rest by really and truly engaging and creating a level playing field. If we do that, the frustrations manifested by that bill will diminish or go away, Sanchez said.

Sanchez, who was in Hong Kong after a visit to Beijing with a delegation of U.S. biotechnology companies last week, said the United States was on track to achieve its goal of doubling exports.

In order for the U.S. to achieve our aim of doubling exports by end of 2014, we need to grow our exports by 14.8 percent each year, he said.

In 2010, our exports increased by 17 percent. In the first 8 months of 2011, exports increased by 16 percent. We are ahead of the curve and it looks like we are very much on track to achieve the president's goal of doubling exports.

(Reporting by Tan Ee Lyn; Editing by Ken Wills and Sanjeev Miglani)