As Rockhampton residents braced for a nine-metre-high major flood this week, efforts were bolstered by some of the 1600 Australian Defence Force troops deployed to help cope with Cyclone Debbie and its aftermath.

In the past fortnight, the military dispatched helicopters, four landing craft, two larger naval ships and conveys of heavy vehicles to deliver water, medicine and other emergency supplies after the category four storm hit.

"Only the military has the large-scale capability of relief response," Michael Thomas, a retired army major, said.

It's a capability that has been tested in recent years, whether from category five Cyclone Winston that smashed Fiji last year or the huge El Nino which brought severe drought to Papua New Guinea.