One case covers Chinese trade barriers that discriminate against American credit and debit card companies that want to participate in China's electronic payments market, U.S. Trade Representative Ron Kirk said in a statement.
The other case challenges anti-dumping and countervailing duties China has imposed on a specialty steel product from the United States, Kirk said.
The request for formal consultations with Beijing on the two disputes came as the Obama administration is under pressure from Congress to take tougher action against China on a number of trade fronts.
Under WTO rules, the United States can ask for a pair of WTO panels to hear its complaints if the two sides cannot resolve the disagreement within 60 days.
Lawmakers in the House of Representatives and the Senate are expected to grill U.S. Treasury Secretary Timothy Geithner in separate hearings on Thursday on why the administration has not labeled China a currency manipulator or filed a case at the WTO against China's currency practices.
"We are concerned that China is breaking its trade commitments to the United States and other WTO partners," Kirk said in announcing the two cases.
Kirk accused China of failing to honor a WTO commitment to open its electronic payments market.
"The Chinese government committed to open this financial service market four years ago -- but instead, the Chinese government is giving China Union Pay a monopoly over most credit and debit card transactions by Chinese consumers," Kirk said.
"China's actions unfairly deprive U.S. credit and debit card companies of access to a huge market."
In the second case, he accused China of imposing anti-dumping and countervailing duties on U.S. grain oriented flat-rolled electrical steel (GOES) to "harass U.S. exports."
"The duties imposed by China have raised the price of hundreds of millions of dollars' worth of American steel headed into China, with the practical effect of reducing or blocking exports of our steel to that country. China must not abuse WTO procedures to protect its market," Kirk said.
U.S. lawmakers on both sides of the political aisle applauded the action, but Senator Charles Grassley, an Iowa Republican, said it wasn't enough.
"The administration should go one step further and bring a case against China's unfair currency manipulation at the WTO. Everyone knows China is manipulating its currency to gain an unfair advantage in international trade," Grassley said. (Reuters)
