On this subject but the technical side, how are copyright holders (movie/music companies) going to be finding / searching for copyright infringers? Seems like that act itself would be some sort of invasion of privacy, interception of data etc...
There is no magic involved. They invade your privacy.
They have software that pretends to be one of the servers you are connecting to, and they send you part of the file they later claim you shouldn't be having. They then assume you took the entire file and send off their email.
It's all very shonky and has failed in court many times overseas.
We will not get that benefit as we are assumed guilty from the start, regardless. The software they use has been proven faulty many times, and in the civilised world this doubt as to it's accuracy - and proven fallibility - would be enough to end it before it starts.
Otherwise they try to get the server records to show you connected to server x and downloaded movie y. Which in itself is falliable (IP spoofing).
Then we have the whole invasion of privacy, privacy act, human rights act, etc. We are supposed to be free from unwarranted searches, supposed to require a court order (with cognizant evidence) before our records can be opened, and punishments must be proportional to the crime (e.g. you pirate a film, you might have to pay the retail dvd price for that film and a fine such as a parking ticket - not the $10,000 they claim overseas - it's way out of proportion).
Are they going to employ people / companies to sniff Internet traffic across NZ?
Yes, and they will be located outside of NZ so they do not have to obey the privacy act.
Half of Youtube seems to have some sort of copyright material yet I don't imagine that will be targeted.
Youtube (Google) has a equally large army of lawyers. In other words, it's not about who is right and who is injured, it's about who can be targeted and made an example of.
The whole thing stinks of collusion at the highest levels of our government, rank ignorance, and out right toadying to large corporations at the expense of you and me.
And it is you and me: who do you think will be paying for these tribunals, enforcement, etc? The taxpayer. Not the rights holder (which is very seldom the author these days).