A plan to double the width of the bicycle lanes on Princes Bridge by removing two lanes of car traffic has been given a major boost after VicRoads approved the idea.

The plan now needs to be approved by Melbourne City Council, which has already set aside $150,000 for the project in its current budget.

Cars may have to make way for bicycles.

A Melbourne City Council spokeswoman said this was the final approval required before the plan went ahead.

"Even though VicRoads has signed it off we can't proceed with the plan until council signs off on it," she said.