LIMA (Reuters) - Peru's new president said Monday it was "worrisome" that China is not part of the 12-nation Trans-Pacific Partnership but his government would seek ratification for U.S. President Barack Obama's signature trade deal.

The U.S.-and-Japan-led pact, reached on Oct. 5 after years of negotiations among a dozen Pacific Rim countries, would slash tariffs in 40 percent of the world's gross domestic product.

The TPP has been pilloried by politicians in the United States. Peruvian President Pedro Pablo Kuczynski, a 77-year-old former investment banker who took office in July, said the sweeping trade pact does not go far enough, though it is good for Peru overall.

"The fact that it excludes China, the dominant power in Asia, is worrisome over the long run," Kuczynski said in a statement distributed by his office.

"It'd be worthwhile to at least research the Free Trade Area of the Asia-Pacific (FTAAP)," Kuczynski added, referring to a more ambitious trade liberalization plan promoted by China that would include the United States and Russia.

U.S. President Barack Obama has marketed the TPP as a way to counter China's influence in the fast-growing Asia-Pacific region as he makes a final push to persuade reluctant congressional leaders to approve the deal in a "lame duck" session after the Nov. 8 election.

Republican presidential candidate Donald Trump has called the TPP a job killer and said Beijing might try to enter the agreement "through the back door" in the future. His Democratic rival Hillary Clinton has said she also opposes the pact.

Kuczynski's comments follow his five-day stay in China, where he met with President Xi Jinping and sought investments for infrastructure projects in Peru, from railways to refineries.

Kuczynski made a point of visiting China, Peru's top trade partner, before any other country as president, in a sign of Chin's growing influence in Latin America.

Now in the United States for the United Nations General Assembly, Kuczynski is scheduled to meet with U.S. Secretary of State John Kerry.

Kuczynski previously said he would seek bilateral trade deals with Australia and other Pacific Rim countries if the TPP dies in the U.S. Congress.

Peru is the world's third-biggest copper and zinc producer and the sixth-biggest gold producer. It also exports fishmeal, cotton and coffee.

Last week Vietnam's parliament deferred ratification of the TPP, adding to uncertainty over the future of the pact.

(Reporting by Mitra Taj; Editing by Cynthia Osterman)