Fears of swine flu spreading to Northern Ireland have increased after the first case of the deadly virus was confirmed in the Republic.

Health chiefs last night confirmed that the infected man, understood to be living in the east of the country, had recently returned from Mexico.

The positive case comes after Health Minister Michael McGimpsey said the executive has been stepping up preparations to deal with a possible swine flu pandemic in the province.

The minister revealed that six new suspected cases of swine flu have emerged in Northern Ireland. All six patients are awaiting test results and are being treated with anti-viral drugs.

Chief Medical Officer in the Republic Dr Tony Holohan said all the people the man has been in contact with will receive anti-viral treatment.

Professor Bill Hall, chairman of the National Pandemic Influenza Expert Group, said the man went to see his GP within hours of returning home.

A total of 12 countries are now being affected by swine flu, including the Netherlands and Switzerland which also reported their first cases yesterday.

Eight people in the UK have been diagnosed with the disease — with the most recent cases detected in London and the North East of England.

There have been 168 deaths in Mexico with eight confirmed as definitely due to the virus, prompting fears of a global epidemic. Other countries affected are the US, Canada, New Zealand, Germany, Spain, Israel and Austria.

At a briefing at Stormont Castle Mr McGimpsey said no cases have yet been confirmed to have the potentially deadly strain. And 14 have proved negative.

He also assured the public about the availability of anti-viral drugs.

“We have also purchased enough anti-virals to treat up to 50% of the population and are rapidly moving to buy enough to treat 75%,” he said.

“Our main message to the public is not to be alarmed about recent developments — but to be prepared for a potential pandemic.”

“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 developments come as the World Health Organisation raised the level of influenza pandemic alert from phase four to five, indicating human-to-human transmission in at least two countries.

Acting chief medical officer Dr Elizabeth Mitchell moved to allay fears adding that preparations are in place to deal with an outbreak.

“The public should not be alarmed and should continue to go about their normal business but to be prepared for a potential pandemic,” she said.

Meanwhile experts said it is unlikely that masks stocked in A&E departments for frontline medical staff would be distributed to members of the public in Northern Ireland. Dr Mitchell said there was “very little evidence” masks gave any benefit to protect people from the virus.

The NI swine flu helpline is now available on 0800 0514 142.