Two soldiers were shot dead by dissident republicans on Saturday
A group of MPs is to review the private civilian security service which guards Army bases in Northern Ireland following the murders of two soldiers.
Commons Counter Terrorism Sub-Committee chairman Patrick Mercer said they would examine if the NI Security Guard Service was an appropriate deterrent.
He said security at bases in Great Britain seemed to be more stringent.
The Security Guard Service was formed after the end of the Army's involvement in operations in Northern Ireland.
"It's very easy to be wise after the event, but I do have to ask why in Scotland, Wales and England if you go to a military barracks there you'll find as a minimum a fully warranted armed MoD policeman and probably an armed soldier, sailor or airman with an automatic rifle standing alongside," he told BBC Radio Ulster.
"I don't understand why there was a difference in the alert levels in Northern Ireland."
The Conservative MP added: "I understand the delicate and critical nature of the political situation in Northern Ireland and the raising of the security profile can have a disproportionate effect upon the political process - the fact remains that lives are at risk."
Mr Mercer said witnesses were being contacted and he hoped the review would take place next month.
"I don't want to pre-judge what we find but I shall be extremely testing on the witnesses, as I'm sure will my colleagues," he said.
Sappers Mark Quinsey, 23, from Birmingham and Patrick Azimkar, 21, from London, were shot dead at Massereene Army base, Antrim, on Saturday evening. Two pizza delivery men were injured.
The Real IRA dissident republican group said it had carried out the attack.
On Monday, the Army's most senior soldier in Northern Ireland, Brigadier George Norton, praised the guards, saying it would have been inappropriate for them to fire into "a closely packed group including my five soldiers".
"Both the guard service and the soldiers did everything that they could possibly do to save the lives of those who had been shot, including obviously the pizza delivery individuals, and I'm delighted by the way they responded but in no way surprised," he said.
On Monday, police constable Stephen Paul Carroll, 48, was shot dead in Craigavon by the Continuity IRA.