Roy Gripskie & sons make some blades locally & are the distributor for Rotary aftermarket blades
Masport are the Stens distributor for their aftermarket blades
JakMax are the distributor for XTH & also a lot of Chinese blades that I for one will not bother fitting.
Alloy Steel Products used to make some blades in Brisbane and import the rest from Europe ( Spain or France )
Oregon blades are distributed through Briggs & Stratton Aust .
Prime Line exited the Australian market around 2005 & they bought out by RGS who abandoned most of their product lines.
However I have noticed that All Mower Spares are now listing a lot of Prime Line parts so they may have done a distribution deal with Prime Line .
RGS & Stens will all open accounts without too much problems provided you have an ABN & TFN.
JakMax usually want you to have a retail shop front but it depend on you convincing the area rep .
ASP will open an account with any body but have the smallest range & the biggest freight charges
Briggs & Stratton will require you to jump through hoops , have a retail presence and have drastically reduced the inventory of Oregon blades ( Gators ) to the point they told me they will not bring in particular lines I used to buy from RGS, they really are only interested in dealing with big multi shop franchises & major retailers ( Bunning etc )
Don't know what is happening with Prime Line but you can always contact them directly
Bad news is the Australian market is tiny volume wise and once we gave up on import duty & quotas increadibly diverse.
So it is big inventories with small turn overs per item line
Domestic owners here do a set of blades every 2 o 3 years on average and commercial customers go through 2 sets a season.
MY commercial customers mostly use Gators , ASP or OEM blades because cost is not as important as quality.
Domestic customers what whatever is cheapest and will happily buy on line if it is 5¢ cheaper than me.
If you go on line, freight is a killer and will usually cost as much as a blade.
And be aware that under Australian laws if you directly import blades you are responsible for product liability so will need insurance .
Some Chinese blades are plain high carbon steel and prone to shattering, World Lawn are particularly prone to this .
Blade factories batch blades to order so if ordering direct from the factory you will need to keep enough till the next run which can be anything up to 3 years away.
Also minimum order quantities start at 100 blades ( for common ones ) and up to 1000 blades for the less common.
Freight rates into Australia for anything that is not a full container is very expensive.