Work has begun on a new inner-city park, in a grey industrial area that could one day be home to tens of thousands of people.

The Andrews government unveiled its design for the future park on Saturday: a grassy, tree-lined public square on what is now a demolition site wedged between two light rail routes and the West Gate Freeway viaduct.

Artist's impression of a $19m park that will open in Fishermans Bend next year.

At a cost of $19 million for 8000 square metres, Fishermans Bend's newest patch of urban greenery will not come cheap for Victorian taxpayers.

The value of land on which the park will be built soared overnight when it, along with 250 hectares of industrial land, was rezoned in 2012.