Wellington, Oct 25 NZPA - The timetable for a referendum on the MMP voting system is "far too prolonged", anti-MMP campaigner Peter Shirtcliffe says.

Justice Minister Simon Power announced this week a first referendum to be held at the same time as the 2011 general election would ask voters whether they wanted to retain MMP.

If they don't they can choose another system from a list of alternatives.

If a majority don't want to retain MMP there will be a second referendum at the same time as the 2014 general election.

The second referendum will be binding and will run off MMP against the alternative that gained the most votes in the first referendum.

Today, Mr Shirtcliffe said it was a "referendum you have when Parliament does not want you to have a referendum".

"There is a perfectly viable simple alternative, which is a one shot referendum in 2011 with, say, four alternatives voted on preferentially and you can get it all over and done with and implemented by 2012."

Current MPs would likely be out of Parliament by the time any changes were implemented under the current timetable and "won't be concerned with the outcome", Mr Shirtcliffe told TVNZ's Q+A.

Trying to tweak or change MMP would "confound the problems", he said.

Green Party co-leader Metiria Turei said the proposed timeline for changes was good.

However, an independent body should oversee it, she said.

"You need to take your time to educate the community and make sure everyone has the information they need and you do it carefully, you don't muck around with electoral systems easily."

There were areas of MMP which could be fine-tuned, such as coat tailing -- which saw ACT with five MPs in parliament despite only having one electorate MP and not meeting the 5 percent party threshold, Ms Turei said.

Mr Shirtcliffe said a recent poll which he was involved in showed people wanted a smaller Parliament than the current 122 MPs.

That could not happen under MMP, he said.

Ms Turei said Parliament in New Zealand was small for its population compared to countries like Norway, Switzerland or Sweden.