Security officials have warned that airport delays are inevitable if they check everything, Taoiseach Bertie Ahern told the Dáil.
He understood the difficulties involved, "but there seems to be no way around this".
He comments came as the Government awaits a report about security breaches at Dublin airport after EU security audit officials got a replica bomb and knives through security on Monday and Tuesday.
Mr Ahern said security officials "have pointed out to me that delays are inevitable if they check everything, particularly if they get quite finicky about every issue as the public probably wants them to be".
He also said that, contrary to some rumours, "no guns or live ammunition were used in the course of the security tests", which are carried out on an ongoing basis at Dublin and other airports.
He was responding to Fine Gael leader Enda Kenny, who called for an audit of airports to determine whether the facilities available to staff "are capable of detecting concealed knives".
Mr Kenny described as "extraordinary" a comment by the Dublin Airport Authority that "passenger safety was not compromised".
He also urged the Government to make a decision on the second airport terminal to make it "more convenient for people to do their business and travel inwards and outwards". The number of passengers was expected to increase from 18 million a year to 30 million over the next 10 to 15 years.
He said 28 outbound flights were delayed yesterday morning as a result of the checks, but "consideration must be had for the travelling public. The officials should be able to do their business safely without compromising the public in terms of time."
Mr Ahern said "people understand the necessity of security searches, and the delays which sometimes arise as a consequence".
He added: "One member of staff contacted me last night to tell me how the knife was concealed, and how detailed a process would be required to follow through on all these issues.
"However this may be what is required. If an incident takes place on an airplane all hell breaks loose. I understand the difficulties for the staff, but there seems to be no way around this."
He said the Government was addressing the growing number of passengers passing through Irish airports. Existing facilities were very modern, and "plans are afoot for the future because the numbers are growing".
Mr Kenny suggested it was not a question of how the knife was concealed but where. People who had hip replacements sometimes set off metal detectors, and he asked: "Are the facilities to detect knives or replica bombs inadequate?"
He believed security breaches would send worrying signals to the US authorities "which are currently involved in a review of airport security systems and anti-terrorist activities".
