Many Australian companies besides those designated as "Shipping Companies" owned their own vessels. These were customarily integrated to facilitate their particular trading and merchanting interests. They also served the nation's war interests.

Among these were:-

• W.R.Carpenter & Company Limited
• Colonial Sugar Refining Company Limited
• Illawarra Steam Navigation Company
• R.W.Miller & Company Pty Limited
• Newcastle & Hunter River Steamship Company Limited
• H.C.Sleigh Company Limited

W.R.Carpenter & Co.Ltd had three major vessels closely associated with Australian trade as the Second World War commenced:-

and their ship the Noorebar, though possibly having been lost in the Rabaul volcano of 1937, is thought to have fallen victim of the Japanese invasion of Rabaul early in 1942.

The ship Rabaul itself sailed the world's oceans as part of the Allied cause until, while under requisition voyage in the South Atlantic, she was shelled and sunk on 14 May 1941, the survivors being imprisoned in enemy hands until war's end.

Colonial Sugar Refining Co.Ltd had three ships at war's start:-

All were engaged in the sugar trade and records suggest all came through the war undamaged.

Illawarra Steam Navigation Co. started the Second World War owning five ships:-

Three ships became "H.M.A.S's" as minesweepers: Bermagui 1939-1946, Narani 1941-1945 and Kianga 1941-1946. The remaining two vessels with determination maintained the New South Wales south coast service, under constant risk amply demonstrated by the number of merchant ship casualties off the coast and also by Cobargo having entered Sydney Harbour on the evening of 31 May 1942, a night remembered as the occasion when three Japanese submarines also entered the Harbour, creating damage and much concern and bringing the awareness of war very much home to the population of Australia's largest city.

R.W.Miller & Co.Pty.Ltd had been well-known as coal merchants on the New South Wales coast and their ships at the start of the Second World War were:-

Bulk carriers, their wartime contribution was an important element in the nation's capacity to cope with the difficult years.

Newcastle & Hunter River Steamship Co.Ltd commenced under this name in January 1892, the product of a merger of earlier separate interests. Its Second World War ships:-

provided New South Wales coastal passenger and cargo services, particularly between Newcastle and Sydney. Records suggest they sustained no losses or damage due to enemy action. The Company ceased to operate as such in 1956 although some ships continued under new company ownership name.

H.C.Sleigh Co.Ltd at the outbreak of the Second World War were operating two trans-Tasman timber vessels:-

and these continued to serve in support of the nation, with no reports of damage by the enemy.