WASHINGTON - A senior White House adviser tamped down expectations on Tuesday for the next rounds of U.S.-China trade talks, urging investors, businesses and the public to be patient about resolving the two-year trade dispute between the world's two largest economies.

"If we're going to get a great result, we really have to let the process take its course," Peter Navarro said on CNBC.

U.S. President Donald Trump's administration is seeking sweeping changes to China's policies and practices on intellectual property protection, the forced transfer of U.S. technology to Chinese firms, American companies' access to China's markets and industrial subsidies.

Trump has imposed stiff tariffs on Chinese imports that have roiled global markets. China has retaliated with its own duties.

Chinese trade deputies are expected to meet with their U.S. counterparts in mid-September in Washington before minister-level meetings in early October in the U.S. capital, involving Chinese Vice Premier Liu He, U.S. Trade Representative Robert Lighthizer and Treasury Secretary Steven Mnuchin.

U.S. tariffs of 15% on about $125 billion worth of goods took effect on Sept. 1, and tariffs on virtually all remaining Chinese imports, including cellphones and laptop computers, are scheduled to take effect on Dec. 15. Tariffs on $250 billion worth of goods are due to rise by 5 percentage points to 30% on Oct. 1.

Navarro said the tariffs were "working beautifully."

"People need to understand this: the tariffs on China are our best defense against China's economic aggression and best insurance policy - this is important - the best insurance policy that China will continue to negotiate in good faith," he said.

The South China Morning Post reported https://bit.ly/2manJ5q, citing an unidentified source, that China was expected to buy more agricultural products in hopes of a better trade deal with the United States.

American and Chinese trade officials would discuss a deal based on a draft text that was negotiated in April before the talks broke down in May, the Hong Kong-based newspaper said.

The U.S. Chamber of Commerce called for a high-standard comprehensive agreement to lift the uncertainty.

"The time is now to strike a deal that addresses the U.S.'s legitimate concerns about market access, forced technology transfer, subsidies, and digital trade, while concurrently removing punitive and retaliatory tariffs," U.S. Chamber international affairs director Myron Brilliant said in remarks to an audience in Beijing.

"Without a truly effective agreement, we don’t see an alternative path to reestablishing bilateral economic stability," Brilliant added.

The U.S. Commerce Department on Tuesday levied preliminary anti-subsidy duties of 104% to 222% on Chinese-made ceramic tiles, a popular item in U.S. home improvement stores.

The Commerce finding that the tile exports were unfairly subsidized affects about $483 million worth of Chinese imports, which have already been hit with 25% tariffs.

(Reporting by David Lawder and Susan Heavey; additional reporting by Mohammad Zargham; Editing by Bernadette Baum, Grant McCool and Sonya Hepinstall) ((202-898-8300; Reuters Messaging: susan.heavey.thomsonreuters.com@reuters.net))