The incoming administration of President-elect Joe Biden will use all available tools to address "China's abusive unfair and illegal practices" that undermine the US economy, Treasury secretary nominee Janet Yellen said Tuesday.

Responding to questions from the Senate Finance Committee at her confirmation hearing, Yellen said China has been "undercutting American companies" with a series of policies, including illegal subsidies, dumping of products, theft of intellectual property and barriers to US goods.

"We need to take on China's abusive unfair and illegal practices," she said, adding "we're prepared to use the full array of tools" to address those issues.

The litany of complaints echoes the central focus of outgoing President Donald Trump's all-out offensive against China, including a costly trade war that imposed billions in punitive tariffs.

However, while Yellen agreed that "China is clearly, our most important strategic competitor," unlike Trump, she stressed that it will be important "to work with our allies" to combat the challenge.

Trump, like other administrations before him, also accused Beijing of keeping its currency artificially low as a way to make its products cheaper and gain a trade advantage, and Yellen repeated the opposition to that practice.

She pledged that the value of the US dollar "should be determined by markets" and "if confirmed, I will work to implement the President-elect's promise to oppose any and all attempts by foreign countries to artificially manipulate currency values to gain an unfair advantage in trade."

She also told senators that global digital tax negotiations under the auspices of the Organisation for Economic Cooperation and Development (OECD) are important for the United States to collect taxes from corporations that have moved their headquarters overseas.

"It would enable us to collect a fair share from corporations, while maintaining the competitiveness of our businesses and diminish the incentives that American companies now have to offshore activities," Yellen said.