The Government is treating as a hoax a suspect envelope containing a white powder that was yesterday delivered to the Taoiseach's office.
Three people have also been arrested and another four questioned by garda∅ in relation to hoax anthrax scares.
The letter, addressed to Mr Ahern and delivered to the Department of the Taoiseach, Dublin, yesterday morning, was opened in an isolated area by one person.
The emergency services, the Garda and the Army were immediately alerted, and the area where the letter was opened was sealed off to prevent any further possible contamination.
The person who opened the envelope, who was not identified by a Government spokesman, was showered and changed, and taken for medical tests as a precaution. He said he did not know from where the envelope was sent.
Garda∅ said the envelope was sent to Cherry Orchard for analysis. Results could take up to three days, said a Garda spokesman.
A Government spokesman said the precautions and procedures advised by the Minister of Health, Mr Martin, earlier this week were followed. The post was opened in the sealed room so the functioning of the rest of the building was not affected, said the spokesman.
"Such hoax alerts should be completely condemned as a waste of valuable time and resources of the emergency services," said the spokesman.
"Such acts will be vigorously pursued and prosecuted," he said. "At a time when the public are rightly concerned at the possible implications of events happening elsewhere in the world, it is unforgivable that there is an irresponsible element in this jurisdiction who would want to increase the anxiety that people are understandably feeling at this time."
Two men in their early 20s were arrested in Arklow, Co Wicklow, after a suspect container was received at a premises in the town yesterday morning. Emergency services were called and the container was removed. One local man was arrested shortly after 11 a.m. and taken to Arklow Garda Station. A second man was arrested in the afternoon and was also detained at Arklow Garda Station under Section 4 of the Criminal Justice Act, under which a person can be held for 12 hours.
In a second case, a man was arrested in Kilkenny yesterday morning. He was later released and a file is being prepared for the Director of Public Prosecutions.
Some four others were also questioned yesterday, one of whom, a woman, came forward voluntarily.
The Garda Commissioner, Mr Pat Byrne, has said the authorities would regard any situation where someone knowingly sent powdered material with a view to causing an anthrax scare, as "a serious matter" and a prison term of up to five years could be imposed, he warned.
There have been 37 reported anthrax scares in the State, including one in Kilkenny on Wednesday. In that incident, emergency services were called to B&C Enterprises when a manager received a small package containing white powder. It later turned out to be flour.
The emergency services have advised anyone concerned about a substance should leave it where it is and call the emergency services.
Mullingar in Co Westmeath became the latest town to fall foul of an anthrax scare yesterday.
Austin Friars Street in the town centre was evacuated and closed for several hours when the call was raised that a suspect white powder was located not in an envelope but in a parking meter.
A traffic warden was emptying coinage from a parking meter when he noticed a suspicious white powder in the machine.
A lab result on the powder will be known on Monday, according to Mullingar Garda∅. Traffic restrictions will remain on Austin Friars Street over the weekend.