Countdown on for Sydney commuter pain

The NSW government has promised an "Olympic-style response" to keep commuter chaos to a minimum when Sydney CBD transport services undergo their biggest overhaul in a generation.

Transport Minister Andrew Constance, Minister for Roads Duncan Gay and CBD Coordinator-General Marg Prendergast on Wednesday announced the establishment of a joint operations centre to oversee major changes to the city's bus routes, which begin this weekend, as well as the planned closure of parts of George Street.

"People are going to experience congestion as they do now but in a way that they haven't before, and we will have teething problems as the bus network comes into operation," Mr Constance told reporters.

A 12-kilometre route is being dug through the heart of Sydney to make way for light rail and a new bus timetable which will be introduced on October 4.