Leading American political figures have seized on the Sam Dastyari scandal to highlight the threats posed by Beijing to Western democracies.

A bipartisan congressional-executive commission on China has heard evidence of growing Communist Party influence in the United States, and towards allies such as Australia and New Zealand.

The donations scandal that ended Senator Dastyari's career this week was examined during a two-hour hearing on Wednesday (local time) chaired by former Republican presidential candidate Marco Rubio.

"Aren't there some recent incidents in Australia of direct intervention in the electoral process?" independent senator Angus King enquired of expert witness Glenn Tiffert, a visiting fellow at Stanford University.

"Yes, and there's great concern in New Zealand as well," said Dr Tiffert, who warned similar activity could also occur in the United States.

Senator Rubio noted China's tactics appeared to be focused on cultivating influential political and academic figures, which differed from Russia's campaign of spreading messages on Twitter during last year's presidential election.

He cited the demise of Senator Dastyari, who had accepted donations from Chinese billionaire Huang Xiangmo.

"What we saw in Australia [was] a member of Parliament resigned after there were accusations made that, not only had he tipped off a Chinese national of some alleged intelligence operation being conducted against him, but that he had allegedly received cash from a wealthy Chinese national," Senator Rubio said.

Echoing concerns of Chinese Communist Party influence at Australian universities, the congressional committee was warned of Beijing's interference on American campuses.

"They are able, through, for example, the Confucius Institute, to promote a particular view of China and to close out discussion of certain topics on campus," Dr Tiffert told the committee.

Shanthi Kalathil, the director of the International Forum for Democratic Studies at the National Endowment for Democracy, testified Beijing was also gaining control of Chinese language media in the United States.

"The aim of buying up media outlets — particularly Chinese language media outlets, but not limited to that — is really to shape a narrative and to constrain discourse about China," she said.