Winter has arrived for hospitals with many feeling a strain on bed numbers despite the number of confirmed cases of influenza falling well below normal levels.

According to figures from the National Influenza Specialist Group (NISG), only 69 confirmed cases of flu were confirmed in the past week across 81 general practices in 19 out of 20 District Health Board areas.

The figures show there is a national consultation rate of just over 18 consultations for every 100,000 people.

A rate of about 50 consultations per 100,000 people was considered to be a normal baseline figure.

This was tracking upwards and was expected to rise considerably however, as the flu season typically peaks in August.

While many flu symptoms are similar to those experienced with a bad cold, medical experts have warned that the disease is much more serious.

Canterbury University virologist Lance Jennings said on average, more people died of flu than on New Zealand roads.

Nearly 400 people die of flu every year, while the road toll for last year was 284.

Jennings said while the number of cases were below the baseline, figures were tracking normally for this time of the year.

"It was unusually high in 2010 because of the pandemic H1N1 virus, more commonly known as Swine Flu," he said.

People rushed to get vaccinated that year, resulting in more than a million vaccines being administered.

The latest figures show 940,750 influenza vaccines have been distributed this year, still well below what medical experts recommend.

"There's a lot of complacency in the community, and that's the only excuse for it. The best protection is prevention," Jennings said.

While the vaccine had been the same for the last two years, Jennings said it was changed in the Northern Hemisphere this year so there will be a change here next season as the current strains of influenza change and mutate.

By 2015, Jennings expected a quadrivalent vaccine to be available - one that protects against four strains of influenza.

Auckland District Health Board emergency department director Tim Park said they were seeing people who had flu-like symptoms, which had into more serious complications, especially in the elderly.

"Our experience of the last week is that we're definitely seeing winter arriving with a vengeance.

"There's always a spike in winter presentations and in this past week especially, there has been an increase in heart attacks among the middle-aged, and serious respiratory illnesses like pneumonia among the elderly.

"It doesn't put pressure on ED so much as it is putting a strain on in-patient beds."

However Park said people were not to be discouraged from coming in to hospital if they needed to, because a bed would always be found.

He said it was important people got their flu shots as early as possible, particularly the elderly. "Ensuring the vulnerable have been vaccinated is the best preventative measure."

A spokeswoman for the Capital and Coast District Health Board said a few cases had been seen through their doors, but it typically got worse in the next few months.

"Anecdotally Wellington Regional Hospital Emergency Department is yet to see a marked increase in the number of patients presenting with influenza-like illnesses. This winter CCDHB has had 3 confirmed cases of influenza in the district."

It was also the same for MidCentral District Health Board.

"A check with our ED department shows we are receiving only a couple of patients a week with flu like symptoms, which is very small compared to the on average 120 patients a day we see at ED," spokesperson Dennis Geddis said.

Flu immunisation is free for New Zealanders considered "high risk" - pregnant women, people aged 65 and over, and anyone with ongoing health conditions such as heart disease, strokes, diabetes, respiratory diseases, kidney disease and most cancers.

Canterbury residents also qualified for free vaccination if they were aged between 6 months and 18 years old to ease the strain on limited beds at Christchurch Hospital due to the earthquake.

- © Fairfax NZ News