Victorian Premier Daniel Andrews has questioned whether an idea for car-free 'superblocks' in Melbourne's CBD "would do much good at all".

The City of Melbourne has released two discussion papers for a new strategy to tackle population growth, and reduce overcrowding and congestion.

The council has proposed car-free zones, imposing a 30km/h speed limit for the city grid, and reducing pedestrian wait times at traffic lights.

It could also reduce the risk of vehicular attacks, like the Bourke Street rampage last year.

The plan, already implemented in Europe and the US, would span several streets, bounded by Bourke, Elizabeth, Flinders and William streets. (9NEWS) (9NEWS)

"Pedestrian crowd crush is a big issue in Melbourne and with the number of people in our city set to grow by 50 percent in the next 20 years, we need to think about how we address that," City of Melbourne Councillor Nicolas Frances Gilley said in a statement today.

"Every hour during the morning peak, 15,000 pedestrians cross the Spencer and Collins Street intersection outside Southern Cross Station, which is five times the number of people in cars, yet cars are given twice the amount of time as pedestrians to pass through."

The zones, already used in Barcelona, could be introduced in parts of the CBD, with shared spaces prioritised for walking, cycling, residents' cars and deliveries, and speed limits reduced to 10km/h.

But Mr Andrews shunned the idea, saying increasing public transport infrastructure like the under-construction Metro rail tunnel is better for improving congestion and safety.

"I'm not convinced that it would improve traffic flow, I'm not convinced it would improve safety," he told reporters.

"I'm not convinced this would do much good at all."