The Government seems to have realised that laws to ban third party advertising during elections are not workable and would probably breach the free speech provisions of the Bill of Rights Act.
Instead they wish to instigate spending limits and official returns. Now in theory this might be attractive (if a party has a limit, why not a third party) but in reality of little effect.
As an example take the Exclusive Brethren. If you have a $100,000 limit, then they could just have ten of their members spend $100,000 each. Likewise the unions could do the same by spreading it around different unions. I’m not sure any limit will be effective.
But more difficult is how do you define what is and is not third party advertising? Is it meant to cover paid advertising and pamphlets only? How will blogs for example be covered? A blog could produce far more responses for a third party than a newspaper advert, yet if you try to force blogs to register and limit what they can say, you’ll be joining the ranks of Iran and China. Would an e-mail campaign by a third party be counted?
I await specific proposals with interest, but I am sceptical that a workable law that doesn’t infringe on free speech can be easily found.