Melbourne will be one of the world's top 10 sustainable cities in 12 years time, if a bold vision for the city outlined today is realised.

Rated a few years ago as the world's most liveable city, and still among the top few, Melbourne is now aiming to emerge at the top of cities spruiking their sustainability credentials.

A draft plan released today envisions a city that, by 2020, has public transport running 24/7, low energy emissions, and a decent chunk of affordable housing.

The Future Melbourne plan, developed over the past year with input from 15,000 people and groups, also hopes to increase the proportion of workers commuting to the CBD without cars from 72 per cent to 90 per cent.

But the city hasn't given up entirely on its liveability ambitions, with a target to regain its number one place on the Economist Intelligence Unit's Quality of Life Ranking high up on its list of priorities.

The Future Melbourne plan was developed by a reference group for the City of Melbourne municipality, which covers the inner city and surrounding areas including Southbank and Docklands.