My product is covered by my Australian patent but another Australian company has copied it and are manufacturing it in Australia and selling it overseas to a country I have no patent rights, are they allowed to do this.
In Australia any act that happens in Australia (sale/importation) infringe the patent even if it happens out of Australia and then imported to Australia.
Even the proposal of sale of some product before the expiration of the patent infringe the patent.
In your case there are sales happening in Australia, no matter the other party is not in Australia. Its like selling something illegal and saying its not illegal because the sale was going to China.
Source: http://www.shelstonip.com/news/federal-court-australia-confirms-offers-made-patent-term-supply-patent-expiry-constitute-infringement/ https://www.wrays.com.au/insights/industry-insights/warner-lambert-v-apotex/
But going to the Patent Act of Australia it goes even more obvious you should sue:
(a) in relation to a product:
(i) make, hire, sell or otherwise dispose of the product; and
(ii) offer to make, hire, sell or otherwise dispose of the product; and
(iii) use or import the product; and
(iv) keep the product for the purpose of doing an act described in subparagraph (i), (ii) or (iii); and
(b) in relation to a method or process:
(i) use the method or process; and
(ii) do an act described in subparagraph (a)(i), (ii), (iii) or (iv) with a product resulting from the use of the method or process.
I have no idea about Australian law, but I think in the US you would be able to sue. I remember hearing in some podcast about a decision of a court that that selling kits for a patented technology to be sold out of the US was not allowed. I don't remember if they were able to get an injunction, but they were allowed damages.
But this is really a hard question and would depend on Australian law.