"We are starting to see an increase in respiratory illnesses," General Practice New Zealand chair Porirua GP Bryan Betty said.
"Those flus and colds you often see in winter are certainly starting to pick up as the weather gets colder."
Children were presenting more often but it was starting to affect different age groups too. Schools are splitting classes up and sending students home as they struggle to find enough relief teachers to cover staff sickness.
"We're only starting the winter illness season now," he said, expecting an increase in cases in June and July.
There were also cases of RSV (Respiratory Syncytial Virus) and adenovirus that GPs were seeing.
"General practice is under more pressure at this point. We know that it can be difficult at times to access your general practitioner," Betty said.
The national telehealth service, which runs 24/7, was a good start if a GP was hard to access, he said.
Health bosses were also pointing people to pharmacies as a first port of call, warning Healthline call volumes increased during winter.
It comes as Te Whatu Ora Health NZ looks at extending telehealth to include overseas-based doctors.
"We are now in the 'flu season'," Otago University epidemiologist Professor Michael Baker said.
It typically runs from May to October in New Zealand.
It was also when the highest rates of influenza, RSV, and other seasonal respiratory infections circulate.
"Currently we are seeing a large rise in RSV infections, and rhinovirus, as well as moderate numbers of influenza cases (including both influenza A subtypes and influenza B)," Baker said.
He said a rise in respiratory infections was in the usual range for this time of the year based on calls to Healthline, and hospitalisations for severe acute respiratory infections (SARI).
'Sharp increase' in Covid cases
Covid had been around all summer, and it was still circulating through the community, Betty said.
"At this point, we're not seeing a huge upswing, however, we would expect to see Covid cases increase over winter."
Baker said while current wastewater testing and hospitalisations showed a "sharp increase in cases, we will need to wait for another week or two to see if this increase is sustained".
Covid was not a "seasonal infection" with cases popping up all year round, he said.
"Some of our largest peaks have been in summer - such as the fifth wave we are currently coming out of."
People should get vaccinated against the flu and Covid, particularly those in an at-risk group, Betty and Baker said.
"Stay home for at least five days if you have respiratory symptoms. Wear a mask in enclosed indoor environments with other people, such as public transport and health care waiting rooms," Baker said.
And Health NZ was also urging people to have a plan and get vaccinated.
For those with pre-existing health issues, who may need more complex medical support, Health NZ primary and community care clinical director Dr Sarah Clarke said contacting their GP was "a critical part of winter preparedness".
"If you have conditions like asthma, COPD or other chronic diseases, make sure you make a plan with your GP practice for if you get sick and, most importantly, ensure you have enough medication to last you through the colder months."
