A prominent security expert has warned that a civilian should not be appointed the new Garda Commissioner.
It had been suggested someone from outside the force would make the best replacement after Nóirín O'Sullivan's shock retirement on Sunday night.
Ms O'Sullivan had been in charge during several controversies including those over inflated breath test statistics and penalty points.
But former deputy director of military intelligence Michael Murphy said the role is too large for someone outside the Gardaí.
He said: "If one of the functions (of the Commissioner's job) is in intelligence and responsibility for the security of the state, and the other in policing then you have to ask yourself why would you put in a civilian in a function that they probably have no background whatsoever in."
meanwhile, there have been a number of call for Ms O'Sullivan's replacement to come from outside Ireland.
Former Northern Ireland Policing Ombudsman, Nuala O’Loan, led those calls.
Ms O’Loan said Ms O’Sullivan’s departure seemed “almost inevitable” because of the serious issues that had come to light during her time at the helm of the force.
“Given the extent of the problems within An Garda Síochána, somebody coming in from outside would have a better opportunity of doing the job,” she told RTÉ.
She added: “They need somebody who has extensive experience, who has experience of change and who has the determination to bring about change.”