NSW's worst flu season not over yet

Spring may have sprung but health experts are warning people to remain alert after NSW experienced its worst flu season on record.

This comes after more than 39,000 cases of influenza were reported in NSW in August - more than double the previous record.

"We're past the peak of the flu season but we expect flu activity to remain high for the next few weeks so it's important not to become complacent," director of Communicable Diseases NSW Health Dr Vicky Sheppeard said in a statement on Friday.

Data collected by NSW Health shows there have been 39,082 cases of the flu during August.

This surpasses the previous record set in July this year when there were 16,761 cases.

In general, August is the worst month for the flu.

In August 2016 there were 13,602 cases, while August 2015 had 12,901 cases.

Already this year there have been 62,948 reported influenza cases, almost double the entire reported cases for 2016.

Dr Sheppeard says the fact that flu notifications had increased by almost 50 per cent in August was due to the more sensitive tests that are available to GPs and emergency departments.

"Our rate of testing for flu in NSW has increased dramatically since 2010 and we now have the most sophisticated flu surveillance system in Australia," Dr Sheppeard said.