A former Hong Kong politician has sold off part of his rare wine collection for over $6 million.

It is believed a wine cellar at his home sparked a scandal that was partly blamed for his loss in last year's leadership race.

The city's former number two Henry Tang was set to become the chief executive in 2012 until a series of gaffes and the discovery of an illegal basement containing the cellar at his luxury home made lead to a fall in his popularity.