Historic $20m Melbourne mansion demolished

An historic $20 million Melbourne mansion is in pieces after demolition workers moved in.

The inside of the five-bedroom art nouveau villa, Idylwilde, is now exposed to the street after bulldozers tore apart the Toorak property on Wednesday.

The property, marketed as "a rare and beautiful piece of Australian real estate", was bought by Chinese entrepreneur Wang Hua in late 2013 for $18.5 million.

"Wow, having seen this house, this is an absolute disgrace," James Saretta tweeted.

Its pool, tennis court and four-car garage remain intact, for now.

The demolition was approved last year by then-planning minister, now-opposition leader Matthew Guy who rejected council appeals to add the property to a heritage register.

The owner, Mr Wang, is believed to also own another property in Toorak worth around $3.5 million, as well as the prestigious Heritage Golf and Country Club in the city's east.

He was also linked to a proposed transformation of financially-troubled Macedon Grammar School and turning it into an elite boarding school.

Those plans were scuppered in December when the school was shut down by the state government.