One example the report gave was the United Kingdom model in which the caucus, the membership and union affiliates have one-third of the votes each.
The review began in February after the party's low election result and the leadership change, during which the party broke with tradition by requiring the contenders for the job - David Shearer and David Cunliffe - to speak at a series of members' meetings. The report said members had valued having input and wanted to make it a right.
The recommendations were also vetted by an external advisory group, which included US-based academic Rob Salmond, businessman Selwyn Pellett, former MPs Margaret Wilson and Tim Barnett and former British Labour MP Bryan Gould.
It said there was concern about the lack of transparency of list rankings.
It also recommended formal affiliation for groups other than the unions. It looked at ways to build its supporters' base - including reduced membership fees for youth and those on low incomes, or a koha system.
It also proposed setting up a "registered supporters" club for groups which were not affiliates, and people who did not want to be members but wanted some involvement.