President Michael D Higgins has convened a meeting of the Council of State today to consider the constitutionality of the Defence (Amendment) Bill.
The Bill passed all stages in the Oireachtas earlier this month.
The Defence (Amendment) Bill 2024 provides a legal underpinning for a new external oversight body for the defence forces.
It also allows for military representative organisations to associate with the Irish Congress of Trade Unions.
President Higgins has highlighted concerns with two sections of the Bill.
Military groups have warned that the proposed law could prevent them criticising Government policy.
The Council of State will meet at Áras an Uachtaráin to consider the constitutionality of the Bill.
Members include the Taoiseach, Tánaiste, senior judges, former presidents and taoisigh as well as individuals added by President Higgins.
Afterwards, Mr Higgins will decide whether to refer the Bill to the Supreme Court for its consideration.
This has only happened 15 times in the history of the State.
Jennifer Carroll MacNeill said the bill intends to 'modernise the Defence Forces' in different ways
Minister of State for European Affairs and Defence Jennifer Carroll MacNeill said the bill is not a gagging order for members of the Defence Forces.
Speaking on RTÉ's Morning Ireland, Minister Carroll MacNeill said it has been clear since 1954 that membership of the Defence Forces is an apolitical activity.
"We are not changing the rules beyond the 1954 and the 1990 provisions which make clear that you sign up to the Defence forces and you do not join, be a member of, subscribe to political organisations and that you are totally loyal to the constitution," she said.
She said the legislation intends to "modernise the Defence Forces" in different ways and enable representative groups RACO and PDFORRA to join ICTU as associate members.
The minister said that this is a step forward and offers representative groups a larger, weightier voice in different ways.
"What we are still doing is maintaining the existing, blanket apolitical nature of the Defence Forces and making it very clear that should persist and that it is a really important part of our Defence Forces," she said.
MS Carroll MacNeill said the aim was to "enhance circumstances" to improve terms and conditions.
She said Defence Force members in uniform cannot participate in a protest.
"But if you’re not in uniform of course you can," she added.