The replacement of the Naval Service's flagship vessel and several of the Air Corps' aircraft are provided for in the defence allocation for Budget 2018.
Minister of State for Defence Paul Kehoe said there will be a "significant" increase of €25 million in defence spending next year, bringing the total Department of Defence funding to €946 million.
Over 25 per cent (€239 million) of defence expenditure will go on Army pensions, an increase of €10 million. There are currently 12,300 military pensioners and this number is increasing, Mr Kehoe said.
The Defence Forces will receive an extra €98 million in long-term investment. This will be used to replace the Air Corps' five Cessna aircraft that date back to 1972 and two Casa Maritime Patrol aircraft which entered service in 1994.
The Cessnas will be replaced by three larger aircraft equipped for intelligence, surveillance, target acquisition and reconnaissance tasks.
The increase will also be used to begin the planning process for the replacement of the Naval Service's flagship vessel LÉ Eithne with a new multi-role ship. A fourth naval ship, the LÉ George Bernard Shaw is due to be delivered in 2018 at a cost of €67 million.
The Army’s fleet of 80 Mowag armoured personal carriers is due to undergo a “mid-life upgrade”.
There is also funding for upgrading military computer and communication equipment and body armour for troops.
Mr Kehoe said the increase in expenditure will allow the Defence Forces to reach its establishment strength of 9,500. The Defence Forces’ current strength of 8,900 means it is struggling to carry out basic duties.
About 750 troops have been recruited so far this year but 200 of them left before completing their training. Meanwhile, about 700 experienced troops retired.
“I remain fully committed to achieving the establishment figure of 9,500 for the Defence Forces,” Mr Kehoe said.
He said the budget will also allow the Defence Forces to continue meeting its overseas commitments with the United Nations.
The 2018 capital funding allocation includes funding for the upgrading of several Army facilities including an ammunition storage facility in the Curragh Camp and the refurbishment of accommodation in Cathal Brugha Barracks.