The Government has announced that new gardaí due to be recruited this month will not now begin training until early September.
The 100 applicants are the first new members to join the force in more than five years.
Minister for Justice Frances Fitzgerald said sanction had been received from Minister for Public Expenditure and Reform Brendan Howlin but did not say why the recruitment had been delayed.
Senior gardaí have expressed concern that the strength of the force has now dropped below 13,000 and the new recruits will not be sufficient to bring the numbers above that figure.
It takes two years before a recruit becomes a fully-trained garda.