The state government has ramped up a pledge to start building the east-west link before next year's election, announcing a short-list of three construction groups jockeying to deliver the $6 billion to $8 billion project.

With state Labor unambiguously opposed to the road, the Napthine government is determined to lock in a contract for the road as quickly as possible, revealing there are three bids being considered.

Hoddle Street overpass looking east showing the new East West Link stage one.

Treasurer Michael O'Brien said the government was ''very confident'' its timetable - regarded by some in the business community as unrealistically tight - would be met, with the design due to be finalised next year and contracts to be signed just weeks before the 2014 poll.

''We have kept to our timetable, in fact we are slightly ahead,'' Mr O'Brien said. ''The consortia that we are engaging with have stuck to the timetables, we are very confident we are dealing with professional people who understand the importance of meeting deadlines.''