Beijing: A Chinese-born man who allegedly assumed a fake identity and obtained Australian citizenship has been arrested by police in Shanghai, who say he spent 18 years on the run after stealing more than $21 million from investors.

Zhang Jianping, who was detained in March, and whose Australian passport lists his age as 51, is believed to be the first Australian national arrested under Operation Fox Hunt, China's broadening operation targeting the return of its wanted fugitives worldwide.

"I don't know who Xie Renliang is. I am Zhang Jianping," the man has said. Credit:Shanghai Public Security Bureau

But Shanghai police say Mr Zhang is actually Xie Renliang, who they allege absconded to Australia under his assumed identity in 1997 with more than 100 million yuan ($21 million) from his failing company.

Police say they identified their suspect through sophisticated facial recognition software as he passed through airport border control. DNA tests carried out after his arrest were cross-referenced with known family members who remained in mainland China. The results proved his real identity was Xie Renliang, police said on Wednesday.