HUNDREDS of kilometres of new freeways and expanded roads would be built across Melbourne over the next 30 years, under plans revealed in a highly detailed government map obtained by The Age.

Road groups and one of Melbourne's most experienced freeway engineers applauded the plans contained in the leaked document, marked Proposed 2040 Road Network Development.

VicRoads would not confirm when the map was produced, but it is believed to have been done with planning authorities as part of a long-term study looking at the city's shape in 2046.