Unfortunately in many cases it is sheer laziness on the part of the listed companies. The relevant law is the law of the place into which the offer is made (sometimes citizenship is relevant as well). Australian law has nothing whatsoever to do with it.
Saying that they have taken advice on the laws of the relevant jurisdictions of their shareholders and been advised that either it is illegal or impractical to extend the offer to shareholders in some jurisdictions is sometimes correct. In other cases it is an outright lie.
As a resident of Hong Kong, I usually get told that I am not eligible to participate in these things. Most companies refuse to even discuss the issue which is a clear disregard of their duties to shareholders because Hong Kong law neither prohibits an offer made to Hong Kong resident shareholders nor requires any form of registration. And, yes, as a Hong Kong lawyer with more than a quarter of a century of experience issuing legal opinions on issues like this one I know what I am talking about.
There are a few companies that I invest in who have actually made the effort to find out what the position is instead of lying to shareholders: AGL and NAB are two that allow me to participate in the DRPs. NUF used to allow me to participate as well.
So if any one feels aggrieved about being needlessly excluded, you should check the position in your jurisdiction and, depending on the answer, call the company.
I sold my CDY shares some time ago after getting fed up with the endless capital ratings that diluted my interest in the company. Things like this just confirm that selling up and moving on to better managed companies was the correct decision.
Good luck to those still holding.
CDY Price at posting:
38.5¢ Sentiment: None Disclosure: Not Held