WASHINGTON (Reuters) - Washington will dispatch its top financial official to Asia to press China on the value of its currency and convince other Asian nations to reach a deal on a free trade pact by year end, officials said on Friday.

Treasury Secretary Jack Lew will visit China, Japan, Singapore, Malaysia and Vietnam next week.

Mr Lew will meet with Chinese officials on Friday in Beijing and will discuss China's commitments to reduce the government's role in influencing the exchange rate for the country's yuan currency, a Treasury official said in a call with reporters.

Washington last month said China's currency was substantially undervalued, which makes Chinese imports cheaper in the United States to the detriment of US manufacturers.

The official, who asked not to be named, said China's exchange policy was a great concern to Washington.

Mr Lew will also press Japan, Singapore, Malaysia and Vietnam to reach an agreement by the end of 2013 on trade pact known as the Trans-Pacific Partnership, a second official said in the call.

The Trans-Pacific Partnership, which would include Australia, Chile, Malaysia, Singapore and Vietnam, would establish a free-trade bloc stretching across a region that makes up nearly 40 per cent of the global economy.