The International Harvester truck factory was opened in 1952. These photographs were taken by the City of Berwick, most likely in the 1970s or 1980s.
The International truck factory was opened by Mr Casey, Minister for External Affairs on June 27, 1952. The factory cost 1,350,000 million pounds to build. It was built on 57 acres of vacant land at Dandenong. It was later joined by General Motors Holden (opened in 1955) and H.J Heinz which also opened in 1955.
The Argus June 27, 1952
From Trove http://trove.nla.gov.au/newspaper
If you want to all about the trucks produced at Dandenong, then I can recommend this book by Peter Lynch. It is available from the Historic Commercial Vehicle Club (HCVC)