When Chinese President Xi Jinping came to power at the beginning of November 2012, one of the first things he did was announce a crackdown on corruption.

Key points: Huang Xiangmo moved to Australia from China at the end of 2012

Huang Xiangmo moved to Australia from China at the end of 2012 First donation to ALP of $150,000 in November 2012

First donation to ALP of $150,000 in November 2012 Since then has donated almost $3 million to both major parties

Since then has donated almost $3 million to both major parties Employed Eric Roozendaal when the Labor powerbroker quit parliament

Employed Eric Roozendaal when the Labor powerbroker quit parliament Huang's friend, Ernest Wong, replaced Eric Roozendaal in NSW Upper House

It was a decision which rippled all the way to the NSW parliament in Macquarie Street.

Among those to be investigated was a political patron of the southern Chinese property developer Huang Xiangmo.

Although Mr Huang was never investigated himself, or even implicated in the case, it created enough uncertainty that he decided to migrate to Australia.

Once he arrived, he set about creating a similar network of political influence through money.

"Every donor expects a pound of flesh in return for their contribution, but in China it's a little more than that," China expert Professor John Fitzgerald told 7.30.

"China's a networked society with very low levels of public trust. Trust is built through relationships and relationships are founded on gifts and donations and favours."

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Half a million dollars donation in one day

Huang Xiangmo's first donation to the NSW Labor Party was $150,000 ( ABC News )

At the same time as Huang Xiangmo was moving to Australia, one of NSW Labor's factional heavyweights, Eric Roozendaal, was being investigated by the state's corruption watchdog, and he was suspended by the party.

Ultimately the ICAC made no findings against Mr Roozendaal, the Upper House member of parliament and former NSW general secretary.

On 19 November, Huang Xiangmo made his first Australian political donation: $150,000 to NSW Labor.

On the same day, two of his business mates donated a further $350,000 between them — all up, half a million dollars in one day.

Eric Roozendaal out, Ernest Wong in

Former NSW treasurer and roads minister Eric Roozendaal was investigated by the Independent Commission Against Corruption in 2012. ( AAP: Paul Miller )

In May 2013 Eric Roozendaal announced he was leaving politics for good.

Unbeknownst to the public, Mr Roozendaal had already secured a job at Huang Xiangmo's company, Yuhu.

Three weeks later a friend of Mr Huang's, Ernest Wong, was catapulted into Mr Roozendaal's Upper House seat.

People within Labor headquarters at the time say it was Sam Dastyari who was the architect of Wong's promotion.

"Where else in Australia would it be possible for a businessman to make significant contributions to a political party and then appoint to his own business somebody invited by his own party to step down?" John Fitzgerald said.

"And fortuitously a colleague or ally, political ally of the businessman finds himself in the seat vacated by the member of parliament who's joined the businessman's firm?"

"I'm sure no laws have been broken but questions need to be asked."

Dastyari's Chinese connections exposed

Sam Dastyari was forced to resign from the front bench over his connections with Chinese businessmen. ( AAP: Lukas Coch )

Since 2012, Huang Xiangmo has donated almost $3 million to both sides of Australian politics.

For Sam Dastyari, the Huang connection would eventually come back to haunt him.

After being elected as a Federal senator in 2013, it was revealed last year that Huang paid a legal bill of thousands of dollars for Senator Dastyari. It also became known that Senator Dastyari allowed another Chinese businessman to pay a travel bill.

Senator Dastyari was forced to resign his position on the opposition front bench.

"The Chinese government tries to exercise influence in Australia through Chinese community organisations," John Fitzgerald explained.

"And a number of organisations with which Mr Huang is associated are, shall we say, fronts for the Chinese government.

"They might be called non-profit organisations or NGOs, but they're set up at the initiative of the communist party and they're funded by business people like Mr Huang."

Neither Sam Dastyari nor Eric Roozendaal responded to 7.30's questions, although Senator Dastyari told the ABC this week that he'd severed all ties with Huang.

Ernest Wong said he could not recall the 2012 donations and rejected suggestions his appointment to the upper house was connected to his relationship with Huang.