Wait a minute.
Looking more into this, even though these people might not be technically illegal, their entrance into the country/known territory is.
"1. The Contracting States shall not impose penalties, on account of their illegal entry or presence, on refugees who, coming directly from a territory where their life or freedom was threatened in the sense of article 1, enter or are present in their territory without authorization, provided they present themselves without delay to the authorities and show good cause for their illegal entry or presence." ~ Article 31, Text of the 1951 Convention Relating to the Status of Refugees/Text of the 1967 Protocol Relating to the Status of Refugees.
So, when they actually recieve their visa, that is when they are considered legal.
Does that mean, technically, they are entering a country illegally, however, when the state is provided with proof of reason for their presence, and accepts them as a refugee, then they are no longer considered an illegal presence?
I stick by my opinion of quickening the visa process, but I don't think that it is completely wrong to call an asylum seeker unauthorized, or to an extent, even illegal (if you're not legal until you gain a visa, then what are you before hand?). It might be Australia's duty to allow them to be assessed and apply for a protection visa, and protect their rights, but without a visa, they still arrive illegally.
It seems a bit contradicting actually. It's perfectly legal to seek asylum under the appropriate circumstances, but when you arrive, you're automatically considered an illegal presence until proven a refugee?
Is there anything in the legislation that undermines this?
I think that's really what the debate (in our current government) is right now. Do we interpret the law to mean they are technically illegal but are granted assistance through the process to become legal refugees or are they're legal refugees by default due to asylum seeker status but this can be revoked later in the process if some other clause is breached?
But you're right, if we're not treating them as asylum seekers, how can they be also illegal too?
The law is very ambiguous in general. There is no right or wrong answer to anything (ie. A rapist that confesses can still find some argument to possibly lower their sentence and has the right to do so; we never just go 'Yup, they confessed. Just lock them up' even if it seems like maximum penalty under the current law is the 'right' answer).
Lawmakers and enforcers also need more than a paragraph of a section of an Act to find the 'best argument'. So really, we don't have enough info in your post to really state a reasonable response to your question.
Personally, as a vegan that aims to reduce suffering overall, I think Australia needs to enforce the relevant treaties and our own laws need to assist with this to defend human rights. We should always strive to improve on this. But it's a very complex issue, it's not as simple as 'being nice to those in need' unfortunately.