Australian former Rio Tinto mining executive Stern Hu has been released from a Chinese jail after nine years.

China's foreign ministry confirmed his release, which came a year earlier than his original sentence due to good behaviour.

There was no sign of the 55-year-old Australian citizen leaving Qingpu prison on the outskirts of Shanghai on Wednesday — the day court documents stipulated for his release.

"While serving his sentence, Hu Shitai complied with prison regulations and discipline and submitted himself to education," Foreign Minister Lu Kang said, using Mr Hu's Chinese name.

"The Chinese justice organs reduced his sentence in accordance with the law."

The Australian Financial Review reported Mr Hu would visit his elderly parents in Tianjin after his release — quoting a source close to the case.

His wife, Zhu Xiaoli, couldn't be reached for comment, nor would the Australian Department of Foreign Affairs confirm anything beyond continuing to offer consular support.

Mr Hu was Rio Tinto's top iron ore negotiator in China during the mining boom, and was instrumental in locking in record prices for shipments to Chinese state steel mills.

But he was arrested in mid 2009, along with three other China-based staff, and convicted in a closed, three-day trial the following year.

"He was a very hard worker, very well connected — of course as an ethnic Chinese, lots of relationships, and he was very well liked by senior executives at Rio Tinto," Philip Kirchlechner, director of Iron Ore Research who worked with Mr Hu prior to his arrest, said.

During his time behind bars, Mr Hu was a model prisoner who helped run the prison library, according to Peter Humphries, who previously wrote about his experience of being jailed in the same prison.

He wrote that the Australian never complained but was dejected by the lengthy sentence, and had heart problems.

The release has raised questions about why successive Australian governments were not more vocal about the lengthy jail term.

"The Government needs to give everyone travelling overseas, including to China, the confidence that they'll be treated fairly when they go there", Greens MP Adam Bandt said.

The arrests and subsequent trials were seen as a watershed moment for western businesses operating in the sometimes-opaque legal environment of China.

"Maybe the company and the employees weren't that sensitive to that risk at the time, I think now companies and individuals would be more sensitive to that risk," Mr Kirchlechner said.

Mr Hu was one of four defendants arrested by China and subsequently fired by Rio. The global miner conducted an internal audit but did not find any wrongdoing by the company itself.

Rio has declined to comment on Mr Hu.