New Zealanders voted in 1993 to change the voting system from the traditional first past the post (FPP) method to mixed member proportional representation (MMP).
In the referendum being held with this year's election, voters will again be asked to decide what kind of voting system they want.
If at least half opt to keep MMP, an independent review will be done to recommend possible changes, such as what thresholds parties must meet to be eligible for list seats, whether voters should be able to change the order of candidates on a party list and whether candidates can stand in an electorate and on the party list.
Mt Eden resident Michele Donovan, who attended yesterday's Keep MMP launch in Auckland, said she wanted to see it stay because it was the "best proportional system", adding that the best way for the current system to be improved was by voting to keep it.
Auckland central resident John Minson, who was also at the launch, said many votes were wasted under FPP.
"If you weren't National or Labour you were completely wasting time. Your vote with the original system didn't count. [MMP] means you have a chance of a minority being heard."
Keep MMP spokeswoman Sandra Grey said the group would continue talking about the benefits of MMP as focus on the November 26 referendum sharpened.
"We can expect a lot of myths about MMP to be touted about over the next few weeks but the facts speak for themselves," she said.
"MMP is the fairest system on offer, where everyone's votes count equally no matter where they live. It has delivered stable governments of the left and right and we have had greater accountability to voters."