Find details of people who travelled to Australia for holiday in early 20th century?

I am trying to find out if my grandfather visited Australia between the years 1918 and 1923 or maybe even up to the start of WWII. I am sure the numbers of people travelling out there would have been limited at that time and am hoping there is a record or register somewhere. Any suggestions would be appreciated.

He could only have travelled by sea and passenger lists are available for most voyages during that period. Some of the genealogy sites may have the info you need such as http://www.genealogylinks.net/australia/all-australia/ships.htm