NSW Heath's Influenza Surveillance Report for the week ending June 9 shows that 155 people in Murrumbidgee were diagnosed with the flu and accounted for 19 per cent of traffic to the ED.

The figure of 155 is a big increase over the 86 cases reported in the previous week in Murrumbidgee.

Statewide, there were 2969 flu cases, up from 2382 notifications the previous week and 49 confirmed deaths.

The early and harsh start to the flu season is considered the reason that public hospitals across NSW have experienced the busiest-ever period in the emergency department between January and March.

"While many people will remember the 2017 winter, our worst flu season on record, we saw thousands more patients this quarter, and these figures do not even show the full winter months," NSW Health deputy secretary Susan Pearce said.

With flu cases still on the rise, people are being reminded by health officials that simple hygiene such as regularly washing hands will help stop the spread of the potentially deadly virus.

Dr Vicky Sheppeard, the NSW Health director of communicable diseases, said while the flu vaccine is still the best protection, simple hand hygiene is also important.

"Basic hygiene can help prevent flu and other infections spreading in the community, so it's really important to cover your coughs and sneezes, and wash your hands regularly," Dr Sheppeard said.

"If you are unwell with the flu, stay at home and minimise contact with other people if possible, especially those who are particularly vulnerable, such as young children and the elderly. Avoid visiting aged care facilities and child care centres until you have recovered.

"It's also not too late to vaccinate and we're encouraging everyone, particularly pregnant women and parents of young children, to arrange flu shots for themselves and their children as soon as possible."