THE spread of swine flu here has accelerated dramatically with 500 people infected in the past week.
The pace at which people are being infected was underlined as two victims fight for their lives in intensive care.
The surge in cases suggests the prevalence of the flu is much more widespread than official figures have previously shown.
Although 276 cases have been officially confirmed through swabs and laboratory tests, GPs have now recorded hundreds of people showing symptoms of the disease in just the past seven days.
As concern grew over the impending scale of the problem, a 30-year-old Slovakian man remained critically ill in St James's Hospital, where he has been treated since Friday after becoming seriously ill in his Dublin home.
A second patient is in intensive care at another hospital -- and a further 10 people have been admitted for hospital treatment since the alert was first raised.
A separate set of figures last night showed the death toll has topped 1,000 as the virus sweeps around the world.
Latest figures published by the European Centre for Disease Prevention and Control (ECDC) in Stockholm show 1,012 deaths had been reported up to yesterday. The figure is almost 200 higher than reported by the World Health Organisation.
A spokesman for the ECDC said the organisation obtains its figures from ministry of health websites, which are more up to date, while the WHO has to await for official notification of deaths.
Swine flu has spread to 30 countries in Europe. Two more deaths were reported in Spain yesterday, bringing the country's total to six deaths.
Here, the Department of Health's chief medical officer Dr Tony Holohan said he was not surprised two people are in intensive care here and said he expects more to be hospitalised in the coming months as well as deaths from the flu.
"Deaths are not going to surprise us or change our public health management," he said.
A spokesman for St James's Hospital said the Slovakian man remained in a critical condition and said all necessary precautions are being taken.
Dr Darina O'Flanagan, head of the Health Protection Surveillance Centre, said the current rate of flu here was 13 per 100,000 population and the rate of increase has escalated, particularly in the last two weeks .
Dr Holohan said it is estimated that at least 500 people who sought treatment from GPs last week across the country showed clinical symptoms for swine flu although they weren't swabbed and lab tested.
This latest disclosure means the 276 laboratory confirmed cases is an underestimate of the level of flu cases here.
Dr Holohan said health authorities here were also changing the previous regime for treatment and would no longer be prescribing the anti-viral Tamiflu for people with mild symptoms or as preventive measure for those who are in at risk groups.
Despite the rise in cases, including the hundreds diagnosed by GPs, it remains a mild illness for the majority of victims and most will recover with no treatment.
However, he said Tamiflu would continue to be given to people who develop severe symptoms and people in at risk groups, such as those who who have underlying illnesses .
The HSE has a group of 136 GP practices across the country which act as watchdogs and feed back information on the numbers of patient with clinical symptoms of the flu.
Swine flu remains a "self limiting" illness for most people which people will recover from, he added.
Dr Patrick Doorley, head of Population Health at the HSE, told a press briefing yesterday it is likely the swine flu vaccine currently being manufactured will be delivered in instalments over six months to a year.
The latest information is that the first batches should arrive here by the autumn and they are working out the logistics of how it can be given to the entire population as stocks become available.
He appealed to the public not to "put pressure" on GPs to prescribe the anti-viral Tamiflu if the doctor does not believe they need it. Just because somebody gets the flu does not mean they need a prescription for Tamiflu, he said.
He added that they are looking at whether a flu phoneline -- similar to that in operation in the UK where someone who describes swine flu symptoms can get Tamiflu prescribed over the phone -- should be set up here if pressure on the service grows. Asked about the availability of intensive care beds in the event of the pandemic worsening over the autumn and winter, he said all hospital managers are working on plans to deal with this level of pressure .