Central Sydney's traffic could soon move at a more sedate pace, with a council proposal to cut the speed limit to 40 kilometres per hour.

The City of Sydney Council has raised the proposal in the New South Wales Parliament in a committee examining road safety.

The speed limit would be cut in an area stretching from Central Railway Station down to Circular Quay, and from Darling Harbour east to College Street and Taylor Square.

The council says there are already 40kph zones within its boundaries, but it wants them extended.

City of Sydney transport manager Terry Lee-Williams says pedestrian safety is a key factor behind the push.

"Over the entire day there are 85,000 vehicles enter the city and there are 600,000 pedestrians enter the city," Mr Lee-Williams said.

"Therefore pedestrians take up a lot more space than the cars take up and they therefore deserve appropriate priority and safety."

The council says a pedestrian hit by a car travelling at 50kph is twice as likely to be killed as a person hit at 40kph.

"It won't change traffic in the peak hour, when most of the people are in the city, because people rarely get above 30kph in the peak hour," Mr Lee-Williams said.

"This really is about the out of peak end shoulder times, when people speed up a little bit but there are still hundreds of thousands of pedestrians in the city."