National Defence is once again taking a look at establishing an around-the-clock 30-minute response time for Canada's search-and-rescue squadrons, an idea the air force has long dismissed as too costly and manpower-intensive.

The Harper government has been under pressure to address the issue ever since a critique last year by the auditor general and the high-profile death two years ago of a young boy in Labrador.

Two reports that examine search-and-rescue incidents and the cost of a 24-7 operation were recently delivered to the headquarters that oversees both domestic and out-of-country missions.

A defence spokesman, Daniel Blouin, would not say what the studies have concluded or when a decision would be made on their findings.

The research builds on a 2008 air force study that rejected the higher level of alert as expensive and only marginally better than the existing framework in terms of saving lives.

In order to meet the around-the-clock posture, the military would need to add between nine and 11 extra crews to the rotations and buy extra aircraft — or reassign existing ones.