The Government has been accused of watering down the remit of the new Oireachtas Committee on Defence and National Security in order to reduce oversight.
Labour Party whip Duncan Smith said a Government proposal was tabled tonight which restricts the definition of "national security" to just cybersecurity, sub-sea networks and other asymmetric threats.
He said such a definition "is far too narrow and excludes so many other threats to national security."
Mr Smith tabled a counter-proposal at a meeting of the Oireachtas Committee on Dáil Reform to "delete this narrow definition and allow the Committee [on Defence and National Security] to begin its work free from arbitrary restrictions."
The Labour Party whip said his proposal was defeated by the Government members "for reasons best known to themselves."
His party plans to bring the issue to the floor of the Dáil tomorrow.
The new Committee on Defence and National Security is due to be chaired by Sinn Féin TD Rose Conway-Walsh.
Her party whip Padraig MacLochlainn, who attended tonight's meeting, has tabled an amendment to the report of the meeting which proposes to "delete the footnote 3: national security encompasses cyber-defence, sub-sea critical infrastructure and related hybrid threats."
The creation of a new Oireachtas Committee on Defence and National Security is just one element of the Government's plans.
It is also establishing a new National Security Council comprising Cabinet ministers, gardaí, senior figures from the Defence Forces and senior Government officials.
The new council will be chaired by the Taoiseach and will review defence issues in Ireland, across the EU and also wider international security developments.
Reacting to tonight's developments, Mr MacLochlainn accused the Coalition of trying "to dilute and limit proper oversight of national security by the new Oireachtas Committee on Defence and National Security."
He said the Labour Party proposal would have ensured "the committee could have full oversight of national security and decide its own work programme as all other committees do."
"This proposal was put to the committee, supported by all the opposition, but voted down by the Government," he added.
A spokesperson for Government Chief Whip Mary Butler said the new committee is thematic and falls under the ambit of the Department of Defence.
They added: "It would not be appropriate for a new committee to be intruding into areas already covered by other committees".
