I did in fact spend a considerable amount of time reading through the bill. With regard to presumption of guilt, the way things are wording truly does not appear to be any different from fairly standard civil proceedings. Here's the specific text:
Infringement notice as evidence of copyright infringement
“(1) In proceedings before the Tribunal, an infringement notice is conclusive evidence of the following:
“(a) that each incidence of file sharing identified in the notice constituted an infringement of the right owner's copyright in the work identified:
“(b) that the information recorded in the infringement notice is correct:
“(c) that the infringement notice was issued in accordance with this Act.
“(2) An account holder may submit evidence, or give reasons, that show that any 1 or more of the presumptions in subsection (1) do not apply with respect to any particular infringement identified in an infringement notice.
“(3) If an account holder submits evidence or gives reasons as referred to in subsection (2), the rights owner must satisfy the Tribunal that the particular presumption or presumptions are correct.
Subsection (3) appears to exist for good reason; if the rights owner can't actually prove the legitimacy of the claim under scutiny, it's no good. Furthermore, should the rights holder overtly lie, there are certainly legal consequences for doing so. That said, if the accused makes no claim to the contrary (likely by not appearing at the proceedings at all), there's no reason for the tribunal not to issue a judgement in favor of the claimant.
Now I'll address the question of attorneys being allowed at the proceedings. Here's the text I believe you're referencing:
“122M If hearing is held
“(1) If a hearing is held, sections 211 to 224 apply, other than sections 213(1) to (3) and 214(1) and (2) sections 213(2) and 214(1).
“(2) Every party to the proceedings may appear personally and be heard.
“(3) A party may not be represented at a hearing by a representative, except as follows:
“(a) a corporation or unincorporated body of persons may be represented by an officer, employee, or member of the corporation or body, or a person who holds a majority interest in it:
“(b) a person jointly liable or entitled with another or others may be represented by 1 of the persons jointly liable or entitled:
“(c) a partnership may be represented by an employee of a partnership:
“(d) a minor, or a person under a disability, may be represented by another person:
“(e) if the Tribunal is satisfied that, for sufficient cause, a party is unable to appear in person or is unable to present his or her case adequately, the party may be represented by a representative approved by the Tribunal:
“(f) if it appears to the Tribunal to be proper in all the circumstances to allow the party to be represented, the party may be represented by a representative approved by the Tribunal.
“(4) A representative may not be a lawyer, unless the Tribunal gives leave.
Bold emphasis is mine for easier reference. A parallel might be small claims court in the U.S.; in a few jurisdictions, attorneys aren't allowed, but it must be stressed that neither party can be represented by an attorney in that case (as is the case with the NZ law). There's also a cap for the amount a judgement can be entered for. In U.S. courts, this ranges from $3,000 to $10,000 USD. This bill references a figure of $15,000 NZD. Using today's currency exchange rates, that's a cap of 11,895 USD.
In short, you may have read the bill, but you did a poor job of actually analyzing it. I'll note that I'm a free software author myself, and choose to publish my code under BSD licensing 99% of the time. However, I respect the rights of others, and I respect the authority of the courts designated to rule on matters such as these. Thus, I am neither a shill, nor misinformed.