BEIJING (Reuters) - China's richest man, Wang Jianlin, said on Tuesday that Dalian Wanda Commercial Properties Co <3699.HK>, the real estate flagship of his Wanda empire, would re-list on the Shanghai Stock Exchange either through an initial public offering (IPO) or a backdoor listing.

Approval for an IPO could take two or three years, while a backdoor listing would require more than a year, Wang said in an exclusive interview with Reuters.

Shareholders of the Hong Kong-listed real estate firm last week approved a buy-out offer that would see the firm privatized. The company said earlier this month it planned to de-list from the Hong Kong stock exchange on Sept. 20.

(Reporting By Matthew Miller and Shu Zhang; Editing by Alex Richardson)