Sam Dastyari has paid the price for his close relationship with a wealthy Chinese benefactor, but his demise has helped to turn a spotlight on the murky area of foreign interference on Australian democracy.

Beijing's rapid and aggressive territorial expansion in the South China Sea is well documented, now its equally insidious global campaign of political intrusions and influence is in full public view.

Western nations, including Australia, insist China's desire for economic and military dominance is not to be resented, but they worry about Beijing's dismissal of international laws such as those governing maritime disputes.

China's habit of crushing internal dissenting views, its attempts to muzzle critical voices overseas, as well as its general disdain for the "rules-based order' — the shared global commitment of all countries to abide by accepted laws and norms — has spooked democratic nations across the world.

Back in late 2015, when a 99-year lease for the Port of Darwin was awarded to Chinese owned company Landbridge, alarm bells began ringing inside Australia's national security community.

For Australian officials, and US allies, the $506 million Darwin deal represented the first big hint that Chinese Communist Party-backed investments down under were not purely economically motivated, but part of a coordinated international drive towards establishing China as a global superpower.

At the time Beijing's controversial "Belt and Road" initiative to dominate global trade was still in its infancy, but the Darwin Port acquisition helped to draw attention to similar strategic Chinese investments being made on Australia's doorstep.

Then came reports of growing anger in some sections of Australia's Chinese population to the Federal Government's stance against Beijing's activities in the South China Sea.

China's Liaoning aircraft carrier conducts a drill in the South China Sea in 2016. ( Reuters )

Most Chinese-language media in Australia is now controlled by Beijing and authorities are increasingly alarmed at the control exerted by the Communist Party on Chinese student groups at Australian universities.

Political donations aid creeping influence

In 2016, Beijing's not-so-subtle creeping influence on Australia's democracy was brought into sharp focus when an ABC investigation revealed Chinese businesses were by far the largest foreign-linked donors to both political parties.

Large donations to major parties, particularly from wealthy businesses, are not unusual in Australia, but even Labor figures were disturbed at Sam Dastyari's decision to have personal debts paid by Communist party-linked businessman Huang Xiangmo, then to subsequently endorse Beijing's controversial foreign policy.

"Today, the Chinese authority operates a very powerful, very resourceful machinery trying to influence the policies of various foreign countries," warns Hong Kong based pro-democracy activist Joseph Cheng Yu-shek.

The prominent academic should know. Deputy Labor leader Tanya Plibersek was due to meet him in early 2015 but was cautioned not to by Sam Dastyari — an action that ultimately contributed to the senator's political downfall this week.

Professor Cheng says Beijing tries to cultivate ties with influential foreign politicians, to persuade them to be friends of China and, as friends of China, to avoid meeting its enemies.

"If these situations become effective, the politicians concerned will be rewarded and then they will be pressured to do something even more compromising later," Professor Cheng explains.

In Hong Kong, Professor Cheng is able to express views which differ from the Chinese state, but his pro-democracy colleagues on the mainland aren't as fortunate.

Earlier this year, Sydney-based Chinese academic Chongyi Feng was detained for a week and interrogated by authorities while on a research trip examining human rights in China.

"Unfortunately a signal of intimidation has been sent to Chinese Australians not to criticise Communist Party interference in Australian domestic affairs," the head of the National Security College at the Australian National University (ANU), Rory Medcalf, observed at the time.

Sorry, this video has expired Chongyi Feng was detained for a week and interrogated by authorities

The Turnbull Government's announcement last week of a sweeping crackdown on foreign interference and political donations drew stinging condemnation from Beijing, but critics say that's a bit rich coming from a country where platforms such as Twitter, Google and Facebook are blocked, and where foreign media reporting is heavily censored.

When Senator Dastyari did eventually fall on his sword, Labor colleagues quickly paid tribute to his advocacy for racial tolerance, victims of banks and for fighting multinational tax avoidance.

But perhaps Senator Dastyari's most important and enduring parliamentary legacy will be highlighting the growing attacks on Australia's sovereignty, particularly from a rising China whose path to becoming a global superpower will be the dominant story of the 21st century.