ACT health officials said on Thursday that influenza cases in the capital have reached the same level as last year, confirming at the same time that swine flu or H1N1 is still very much around in Canberra.

As of this week, 72 confirmed cases of influenza have been recorded in the area, according to CT Chief Health Officer Paul Kelly, noting too that more were believed to be suffering from respiratory-related complications.

Majority of the laboratory cases were reported by various hospitals in the capital in May, Dr Kelly added, further highlighting health officials' assertions that flu strains ramp up their circulation depending on the prevailing season.

The Health Directorate also warned that specific group of people were being considered as high-risk, meaning they could develop a host of complications once they contracted flu strains.

"(They) include people over the age of 65, Aboriginal and Torres Strait Islanders people over 15, pregnant women and anyone over six months of age with an underlying medical condition that predisposes them to the risk of complications from influenza," ABC reported Dr Kelly as saying in his advisory.

He added that extra caution should be observed by people with "chronic heart and other chronic diseases."

Reports coming since last month indicated that flu cases were seen in nursing homes, schools and even work areas as Dr Kelly reminded that resistance from the flu strain can be boosted by getting shots of vaccines offered in clinics and hospitals.

"Flu is very contagious so people should be reminded that if they do have symptoms of flu to not soldier on," the city's top doctor was reported by The Melbourne Weekly Eastern as saying.

"It's best not to soldier on and to help their own health as well as decrease the risk too others. And if you are coughing and sneezing, cover your nose and mouth, dispose of used tissues into the bin and wash your hands regularly," he added.

Dr Kelly affirmed too that swine flu appears to be in circulation in Canberra but not in the magnitude that was seen in 2009 when the pandemic officially killed 191 people in Australia and more than 18,000 worldwide, based on figures furnished by the World Health Organisation (WHO).

"The swine flu strain from a couple of years ago seems to be decreasing as a proportion ... (but) another A-strain, the H3N2 strain, at the moment at least seems to be increasing," Dr Kelly said.

All strains, he added, are included in the flu vaccines currently available in Australia.

The ACT health advisory was issued following the report published earlier this week by The Lancet Infectious Diseases journal, which claimed that between 284,500 and 575,400 people died from the swine flu pandemic that global health experts said started claiming lives as early as April 2009.

The new report countered the official estimate issued by the UN health agency, which in turn affirmed that up to half-a-million people die yearly worldwide due to various flu strains.

"Laboratory-confirmed deaths are gross underestimates of influenza-related mortality because of the lack of routine laboratory tests and difficulties in identification of influenza-related deaths," Agence France Presse (AFP) quoted the report as saying.

The new report, according to lead author Fatimah Dawood of the U.S. Centre for Disease Control and Prevention (CDC) "can be used not only to improve influenza disease burden modelling globally, but to improve the public health response during future pandemics in parts of the world that suffer more deaths."

Her team's work, Dr Dawood added, should be employed too in increasing "the public's awareness of the importance of influenza prevention."