Iowa Governor Terry Branstad is a step closer to becoming US ambassador to China, as a Senate panel approved his nomination on Tuesday, a week after his confirmation hearing in Washington.

The US Senate Foreign Relations Committee approved the 70-year-old by voice vote, with the committee's top Democrat Ben Cardin describing Branstad as "fully qualified" for the job.

Branstad still must be confirmed by the full Senate on a date to be announced.

The likely new face of America to the Chinese people has a relationship with President Xi Jinping that dates back to his first term as governor in 1985, when Xi was visiting as a county leader from North China.

US President Donald Trump told Branstad during his presidential campaign in Iowa: "Boy, you would be our prime candidate to take care of China."

"If confirmed, I hope to use my unique position as an old friend of President Xi and a trusted confidant of President Trump to positively influence the US-China relationship," Branstad said on May 2 during his confirmation hearing.

He also said that the US relationship with China is multifaceted, not solely focused on trade, and he was aware of the critical national security issues, including on the Korean Peninsula, that the two countries must work together on as well.

Despite being an old friend of China, Branstad would have to be clear to the American people about putting "America's interests first", observed David Lampton, former president of the National Committee on US-China Relations.

The professor and director of China Studies at Johns Hopkins University said Branstad should try to establish as good of a relationship as he can at the highest level possible.

"He should try to become a major conduit between leaders and get the ability to call the president -when there is a big problem," Lampton told China Daily, alluding to the close relations between US ambassador Clark "Sandy" Randt enjoyed with president George W. Bush in the 2000s.

J. Stapleton Roy, US ambassador to China between 1991 and 1995, suggested Branstad "be himself" and not try to become who his predecessors were.

"You need to be able to convince the other side that you have a genuine interest in improving the relationship," Roy said.

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