Liu Han, 48, the former chairman of Hanlong Group, was executed along with his brother, Liu Wei, and three associates, official news agency Xinhua reported.

The men met with their families before they were executed, Xinhua said.

Liu has been linked by state media to former security czar Zhou Yongkang -- the most senior official snared in China's anti-corruption campaign.

Hanlong's interests included mining, real estate, electricity, energy and finance and the company remains a shareholder in two Australian companies - Moly Group and Sundance Resources.

Liu was detained in 2013 along with his younger brother. They were sentenced to death in May 2014.

The Liu brothers started out running gambling dens in their base in Guanghan, in China's southwestern Sichuan province, in the early 1990s, gathering around them "a gang of local thugs and vagrants," state media reported around the time of their trial.

The brothers' empire grew, before finally attracting the attention of central authorities with an alleged public shooting at a Guanghan teahouse one afternoon in January, 2009, supposedly ordered by Liu Wei and directed at an underworld rival.

Liu Han also developed a reputation as a philanthropist, building a rural school campus following a 2008 earthquake that devastated Sichuan. His brother also had a reputation for charity, and had been a torch-bearer in the build-up to the Beijing Olympics, also in 2008.