Sweden saw an unusually high number of registered cases of flu in the last two weeks of February, new figures from the country's Public Health Agency show.

"We have not seen this many cases of seasonal flu since we started keeping records in 1993," Anna Sara Carnahan, an epidemiologist at the Public Health Agency of Sweden told newspaper Dagens Nyheter on Thursday.

"In week seven this year, there were 950 lab-confirmed cases of flu and the week after the number was almost as high: 948. We know this is just the tip of the iceberg since most people do not seek hospital care. Normally, we count on the real number being between 100 and 1,000 times higher than the recorded one," Carnahan said.

Systematic measurements of laboratory-confirmed flu cases started in 1993 and since then diagnosis has improved. In addition, since 2009, the number of tests carried out has increased, too.

Still, the Public Health Agency of Sweden stated that the number of registered flu cases in the past two weeks far exceeds any previous recorded figures, with the exception of the swine flu outbreak in 2009.

However, at that time more tests were carried out than usual since many Swedes who fell ill were particularly concerned and sought medical care.

During winter seasons with unusually high levels of flu, the number of deaths in Sweden tends to increase by between 1,000 and 5,000. Those most at risk are the elderly and people with previous medical conditions.

Vaccinations against the most common forms of flu are recommended for at-risk individuals.