I would like to plant thin trees to about 3mtrs- advice?

In the US most suppliers use a zone map. Shows what areas are good to different kinds of plants based on average heat/rain/cold. Does Australia have anything like that? Maybe something weather person keeps track of. Plant nurseries should have an idea of what would wo

Italian Cyprus is evergreen - maybe suitable

Here are your planting zones: https://www.gardenia.net/guide/australian-hardiness-zones

Perhaps you could tell us which zone you're in and are you looking for privacy? Can your trees be taller than 3m?

Here are some suggestions for Zone 8, if that happens to be your planting zone:

‘Rasen’ Japanese Cedar (Cryptomeria japonica ‘Rasen’): 8 feet high by 3 feet wide

‘Sky Pencil’ Holly (Ilex crenata ‘Sky Pencil’): 8 feet tall by 1 foot wide

‘Tsukasa Silhouette’ Japanese Maple (Acer palmatum ‘Tsukasa Silhouette’): 20 feet tall by 4 feet wide

‘Twisted Growth’ deodar cedar (Cedrus deodara ‘Twisted Growth’): 12 feet tall by about 3 feet wide

‘Cumulus’ Alleghany serviceberry (Amelanchier laevis ‘Cumulus’): 15 to 25 feet tall and 10 to 15 feet wide

‘Viridis’ Japanese maple (Acer palmatum var. dissectum ‘Viridis’): 4 to 6 feet tall and 8 to 10 feet wide

I would call your local landscaping company or someone that does a tree service; everyone has them in their area and if not they still can give you answers---good luck

OK so to us your location is confusing. Where do you live and what are your lighting conditions,and how much room is there????