The move follows the World Health Organisation's announcement that the current level of influenza pandemic alert had been raised from phase 4 to 5.
Dr Mitchell said: "WHO's decision to raise the pandemic alert to five means that they consider a global pandemic to be imminent, and everyone must ramp up their pandemic preparations. In Northern Ireland we are already doing this and continue to work very closely with our counterparts across the UK and in the Republic of Ireland.
"The key message to the public is not to be alarmed but to be prepared for a potential pandemic. Evidence to date suggests that, other than in Mexico, the majority of cases have had a relatively mild flu-like illness which responds well to treatment with antivirals.
"We have been planning for a situation like this for some years. In fact, the UK is recognised as among the best prepared for any potential pandemic. The preparations we have in place and are continuing to make, will help us respond well in the event of a pandemic.
"GPs across the country have been notified and made aware of the symptoms and what to do if they suspect a patient has pandemic flu. We have also purchased enough antivirals to treat up to 50% of the population and are rapidly moving to buy enough to treat 75%."
Antivirals will reduce the severity and length of the illness and reduce the risk of transmission.
Dr Mitchell continued: "If you have returned from a swine flu affected area and have flu like symptoms, stay at home and call your GP for further advice. The public can take simple but effective measures to protect themselves including, frequent hand-washing and using a tissue to cover your mouth when you cough and sneeze."
A Northern Ireland swine flu helpline number is being established and is expected to be available from tomorrow afternoon. The number to contact is 0800 0514 142.
Notes to editors:
- Further information on swine flu can be found on the DHSSPS website and nidirect website
- In addition to the Northern Ireland Swine Flu Helpline number above, there is a national UK-wide helpline where you can hear advice on swine flu contact 0800 1 513 513.
