ABF SmartGates at MEL, SYD and BNE apparently failed at around 0600 hours on Monday 29 April 2019, so the inevitable result is extremely long queues of passengers waiting to be manually processed. If I recall, there are fewer outwards desks for ABF staff with SmartGates than was the case before these were widely in use, so that won't assist timeliness.
As the peak time for departures to Asia starts in an hour at the three major east coast airports, expect flights to incur delays through no fault of their own or the airline staff. Even if all passengers for a flight were checked in an hour before scheduled departure, it's unlikely flights would get away on time. At departures immigration, it would be difficult to 'call forward' passengers whose flights were almost scheduled to depart.
VA1, the 0930 hours SYD - LAX is predicted to depart half an hour late while the 0900 hours VA171 (SYD - WLG) should depart at 1130 hours.
UPDATE: The expected departure for VA1 is further delayed to the strange time of 1029 hours.
FURTHER UPDATE: B773ER VH-VPH on VA1 took off from SYD at 1116 hours so an 0638 hours, 33 late arrival is expected in LAX.