So much is happening down just this side of the street. As busy as it is, all those pedestrians look very orderly. Especially for the lunch-time rush hour (the clock in the centre shows 1:10pm). They look more orderly than the cars heading towards the double-decker bus in the background.
Note the line down the middle of the footpath and the pedestrains keeping left.
Digital ID: Martin Place, Sydney 17 Sep 1962 NRS21573_2_PR004761_c
The Dictionary of Sydney tells us that
"In the late 1960s, there were new proposals for Martin Place between Pitt and George streets to be closed to traffic to create a pedestrian plaza. Stage 1 of the plaza was opened in September 1971, and was such a popular success that approval was given to extend the pedestrian precinct through from George Street to Macquarie Street. This was done in stages over the 1970s, with the final section opened in 1979, to coincide with the opening of the Martin Place railway station of the new Eastern Suburbs line."