Yes.
I have imported a left-hand-drive Chang-Jiang M1M outfit into Queensland and successfully registered it.
Basically I had to make certain I had purchased a bike which had genuine paperwork proving it was more than 30 years old.
I then had to get a Vehicle Import Certificate from DOTARS in Canberra.
Then I arranged for the bike to be shipped from Beijing to Brisbane.
After Quarantine and Customs clearances, I got a CTP insurance covering the bike which would commence on a certain day when I had no other appointments. On that day I rode it to The BM Shop near home, got my Safety Certificate first go, rode it to the Transport Queensland offices, registered it and rode it home again.
My paperwork shows that the bike was manufactured in May 1962 and that it was first registered in China in August 1962. This of course had to be translated into English. By making sure that my frame number dated the bike as 1962, it meant that I did not have to make heaps of modifications to make it meet up to ADRs.
It is impossible to import a bike that is legally a 2003 model, for example, since every part of the bike must conform to whatever ADRs were in force at the date of manufacture.

If you have other questions, I'll be happy to answer them.

Whoops, on re-reading John's original post, it seems you might be asking about a symmetrical trike.
To do that, I think you would need to import a standard CJ as above, register it, and then rebuild it into a trike here following whatever regulations are necessary.

Thanks Phil for the info on age-of-vehicle documents, etc but I was specifically enquiring about existing three-wheelers:
Namely the CJ-based threewheel truck shown:
http://www.changjiangunlimited.com/2007/06-0922-Xitek%20(3).jpg
http://www.changjiangunlimited.com/2007/06-0922-Xitek%20(22).jpg

and the Ural IMZ-8.401:
http://www.ural.com.au/workhorse.html

I imagine that these vehicles may be easier to upgrade to Australian requirements. These include brakes, instrumenttion, clearance lights, and high-mid mounted brakelamp!

With the Xitek that age-of-vehicle documentation may well be still important.

Regards,
John
PS. I have owned a Vespa Ape back in the sixties, Later on I had a BMW R50/5, a BMW R25, and a BMW R75/6.