This will vary throughout the country, but clearly, plants cannot be put into dry soil.
Assuming thorough weed control has been achieved and the soil moisture from rain (or in some cases irrigation) is adequate then as a general rule around August September in Victoria, the south coast of NSW, and the colder higher parts of NSW extending up through the New England area into the granite belt in Queensland.
Along the coastal strip of NSW say north of Sydney and Queensland after the opening of the summer rainfall season maybe around November would be a suitable planting time.
November – December planting will be OK in low rainfall areas such as those irrigation areas in the Murray Darling Basin.