Dr Pat Doorley of the HSE said it is hoped mass swine flu vaccinations will start at clinics in October.

A number of sites have been identified for the clinics, which will require a significant redeployment of nursing, medical and other staff.

Meanwhile, Department of Health Chief Medical Officer Dr Tony Holohan has said the number of cases of the H1N1 virus are expected to increase from now on.

In the last week, there have been six outbreaks in schools but there has been no need to close any school.

The number of new cases diagnosed by GPs has doubled to around 3,300 a week, according to new figures released this evening.

The Department of Health and Children says, to date, 147 people have been hospitalised.

Of the 23 patients who remain in hospital, eight are in intensive care.

The HSE has also asked people in at risk groups to also get the normal seasonal flu vaccine.

Read the HSE's information on swine flu

The HSE's 24-hour flu information line is available on freephone 1800 94 11 00.