Record numbers of patients are swamping NSW emergency departments, with patients in western Sydney experiencing the longest delays, the opposition says.

NSW hospitals are struggling to cope with demand as patients swamp emergency departments in record numbers, the state opposition says.

New Bureau of Health Information (BHI) figures show more than 664,000 patients visited the state's emergency departments between October and December 2015 - a jump of two per cent on the previous year - or 900 more people each week.

Opposition health spokesman Walt Secord said treatment wait times for more than a quarter of those patients exceeded four hours.

Emergency patients at the western Sydney hospitals of Liverpool, Westmead and Nepean experienced some of the longest delays in Australia, he said.

"Sadly these are not just numbers, they have a human face," Mr Secord said in a statement on Wednesday.

"They are thousands of mothers, fathers, children and grandparents who rely on the health and hospital system."

Health Minister Jillian Skinner blamed the surge on a severe flu season but she said NSW hospitals continued to perform at the highest standard despite the record influx.

She said the BHI figures showed emergency wait times had improved since 2010 and elective surgery waits remained stable.

"Our hospitals continue to deliver high-quality and timely care," she said.

However, the Australian Medical Association of NSW said hospitals are straining to cope with the record patient numbers and warned treatment delays would only get longer.

AMA President Saxon Smith said the figures highlighted the dangers of federal government cuts to health funding, which would hit home in 2017.

"Hospital staff are working more efficiently than ever but they are just swamped with demand," Dr Smith said.