The Joint Oireachtas Committee on Foreign Affairs and Defence has been urged to visit Naval Service headquarters to investigate for itself how bad manpower levels are.
It has also been asked as a matter of urgency to speak to senior commanders in the Defence Forces to ascertain the true extent of the manpower crisis which forced the Navy to tie up two ships.
The requests have been made to the committee by Senator Gerard Craughwell, a former member of the Defence Forces, and come following a row between minister with responsibility for Defence, Paul Kehoe and some military commanders over the reason for tying up two ships.
Taoiseach Leo Varadkar waded into the controversy, siding with Navy claims that staffing shortages are to blame for the docking of LÉ Eithne and LÉ Orla.
Mr Varadkar was asked to clarify confusion after concerns that Mr Kehoe had contradicted and undermined a commander in the row.
Mr Kehoe claimed the vessels are docked for maintenance reasons. But Commodore Mick Malone, the Navy's most senior officer, said they were taken out of service because of inadequate staffing levels.
“As you know, the Navy has been short-staffed for quite some time. As we approach full employment, lots of people are finding it hard to get staff. And the Navy is one of those areas. So rather than spreading the crews over seven ships, they are now going to fully staff and fully equip five and two will go into maintenance in the meantime," Mr Varadkar said.
I think the flag officer described it as 'cutting the cloth to fit the measure' and that is what is going to be done.
Meanwhile, the Irish Maritime Forum has accused Mr Keogh of "throwing Commander Malone under a bus".
In a statement, it said this was "entirely dishonourable" and Mr Keogh was probably aware that Commander Malone "wouldn't contradict him because of military discipline".
Mr Keogh tried to defend himself yesterday by again saying that the ships had to be tied up for maintenance, but admitted that the Naval service faces staffing issues and is only at 88% of its required strength.
Mr Craughwell said he has written to the Oireachtas committee chairman, Brendan Smith, requesting a visit to the Navy's headquarters in Haulbowline so its members can get an accurate picture of the manpower crisis.
"There needs to be an external investigation into this immediately. Foreign direct investment depends on strong Defence Forces," Mr Craughwell said.
Fianna Fáil spokesman on defence, Jack Chambers, said Mr Kehoe has clearly contradicted Commodore Malone and also dragged Chief of Staff Vice Admiral Mark Mellett into the controversy "which was totally inappropriate".
He said Mr Kehoe has "undermined" the two senior officers.
"It's well-known the Navy plans ship maintenance months in advance and in the case of at least one of the ships this was not due to take place until September," Mr Chambers said.