Five of the state's big public hospitals have recorded a significant improvement in emergency waiting times.
The Bureau of Health Information's quarterly report reveals more than 600,000 people visited emergency departments between April and June this year, and almost three-quarters left within the target four hours.
But this still falls short of the nationally agreed target, which requires hospitals to process 81 per cent of these patients within four hours.
The report also found 85 per cent of emergency patients were transferred from ambulances to hospital within 30 minutes of arriving.
The bureau's chief executive, Dr Jean-Frederic Levesque says Bankstown, Macksville, Sutherland, Hawkesbury and Royal Prince Alfred hospitals all performed better this quarter.
He said the majority of patients are leaving emergency wards more quickly and the time frame is the shortest for this quarter over the past five years.
"There's been quite strong improvements as well, with regards to the proportion of patients that leave the emergency department within four hours in some larger metropolitan hospitals that used to have lower results," he told ABC radio.
These figures come as the volume of services increased.
"Hospitals recorded two per cent more admitted patient episodes and three per cent more patients visiting emergency departments... compared to the same quarter one year ago," Dr Levesque said.
But Opposition Leader John Robertson says the new health figures for the April-June quarter show the performance of almost every western Sydney hospital is falling short of targets, and sliding backwards since the January-March quarter.
He said at Westmead Hospital, patients with urgent conditions such as blood loss or dehydration are waiting on average 29 minutes to even begin treatment - significantly above the State median of 20 minutes.
"From Westmead to Campbelltown to Nepean, patients are suffering as hospitals reach breaking point," Mr Robertson said.
"Mike Baird has cut $3 billion from NSW hospitals and he has failed to stand up to his Liberal mates in Canberra who have cut $15 billion from the State's health budget."