There has been a significant increase in the number of new swine flu cases in the past week, officials confirmed this evening.
The latest figures from the HSE show that the infection rate for flu-like illnesses is almost double that of last week.
There are now almost 1,300 confirmed cases of swine flu in Ireland.
The HSE say they expect vaccination of the public to begin in October, and will need an additional 2,000 staff to administer the vaccines.
The State’s Chief Medical Officer Dr Tony Holohan said the latest figures suggest the virus could be entering a new stage.
“We've seen a significant increase this week as compared to last week in a number of the rates that we follow,” Dr. Holohan said.
“What that will translate into next week we will obviously have to wait and see, but we are certainly prepared for a situation that that might be implying that we're in the start of an acceleration phase.
“I can't say with certainty what's going to happen next week but certainly our assumptions are that that's what we could be looking at.”
The spread of swine flu in the North also continues to gather pace ,with GP consultations up for the third week running, according to official figures released today.
The latest Department of Health weekly swine flu bulletin revealed there had been another 42 laboratory confirmed cases, an escalation on the total last week and bringing the number in the North to 275.
Anti-viral prescriptions increased to 571 in the week compared to 408 the week before and the number issued since the alert began broke through the 10,000 barrier.
The number of people admitted to hospital because of the flu increased to 126, said the department.
The number of deaths remains two.
The highest number of GP and out of hours consultations over flu continued to be with patients in the 5-14 age group.
The North's Chief Medical Officer Dr Michael McBride said they were "keeping a close eye" on the rise in calls to doctors and out of hours services, which were significantly higher than those for flu-like illness at the same time last year.
But he assured the public: "Primary care services continue to cope well despite the increased demand on their services."