Mystery surrounds the latest social media foray by Chinese mining magnate Sally Zou, whose most recent tweet shows a cheque for $1.2 million made out to the SA Liberals, money the Opposition Leader Steven Marshall says has not been received.

Ms Zou is one of the state Liberal Party's biggest donors, with her AusGold Mining Group providing the party with hundreds of thousands of dollars within the past year alone.

It is not clear if the $1,212,018 donation has been paid, but the tweet — which has since been deleted — came accompanied with an obscure message.

"This is a life-journey wandering the Man, who met is a beautiful accident," Ms Zou tweeted.

"Perhaps is casual transmigration, and this was born, wish you LIBERALS had enough."

The tweet shows a cheque made out for more than $1.2 million. ( Twitter: @sally_ausgold )

Labor Treasurer Tom Koutsantonis said the SA Liberal leader needed to explain the party's link with the businesswoman.

"At a time when the Commonwealth Government are passing legislative reforms to stop Chinese influence in Australia, the state-based Liberal Party under Mr Marshall is accepting record donations from this mysterious Chinese businesswoman," he said.

"Mr Marshall has admitted under questioning that he's met with her.

"What did he say? What did she ask for? What was their conversation about?"

In a statement, Liberal state director Sascha Meldrum said "the Liberal Party has not received the donation" that was depicted in the tweet.

"We strictly follow the legislation regarding donations which requires donations over $5,191 to be disclosed publicly within seven days of receiving it," she said.

'No big cheque received'

Questioned about donations at a news conference, Mr Marshall told reporters: "Look, we are open to donations in the Liberal Party, don't get me wrong, we would love people to help us get rid of this tired, dysfunctional 16-year-old Labor administration," he said.

Steven Marshall says the Liberals ensure they comply with disclosure laws on donations. ( ABC News: Nick Harmsen )

"But no big cheque has been received in the mail recently.

"And we have been reporting all of the donations that have come through in accordance with our very strict legislation which is required here in SA."

When contacted by the ABC, Ms Zou immediately hung up, but sent a text shortly afterwards saying she "can't talk now. Thanks for your understanding".

There has been a total of $2.3 million in disclosed political gifts since late 2015.

If true, the donation would be by far the biggest to any candidate or party ahead of the state's March election.

Little is known about Ms Zou, who closely guards her public profile and has an enigmatic social media presence, often tweeting then deleting.

She has a penchant for running full-page advertisements in newspapers on subject matter ranging from real estate to food.

Ms Zou is also a key sponsor of the Port Power AFL club, and last year provided $88,888 in a single donation to the Liberals (eight is considered a lucky number in China).

In October, Attorney-General John Rau updated electoral regulations to require all foreign donors to declare their allegiances.

Ms Zou took out this ad in The Advertiser newspaper last year. ( The Advertiser )

Under new election expenditure caps, the Liberals are entitled to spend up to $4.025 million on election campaigning between January and April 17 — a month after the March election.

Breaches to the cap would incur losses of taxpayer funding.

A gift of the size of $1.2 million would have to be reported to the state's electoral commission within seven days.

The Federal Government has put moves in place to ban foreign donations amid concerns about Chinese influence in the wake of the Sam Dastyari scandal.

Ms Zou made headlines last year after setting up a company named after the Foreign Minister, called the "Julie Bishop Glorious Foundation".

Ms Bishop was quizzed in Parliament, and insisted she had never heard of such a foundation until the matter was raised with her by the media.