I've identified two books of poems by Jack Sorensen. They are not viewable online, but if you follow the links and enter your postcode, it might show you where to find them in a library near you:

Sorensen, Jack. The Gun of Glindawor and Other Ballads. Perth [W.A.]: P.S. Sampson Brokensha Co, 1932.

Sorensen, Jack. The Lost Shanty: And Other Verses. Perth: Sampson Printing, 1939.