Rather than kicking the tyres of MMP, the Government is putting the whole car up for sale, a political expert says.
Victoria University's Dr Jon Johansson told the parliamentary committee that is considering legislation for an electoral referendum on MMP that it was unnecessary.
The referendum was an election promise from National and Prime Minister John Key has said it wouldn't hurt to kick the tyres.
"Rather than kicking the tyres we are putting the car up for sale," Dr Johansson said.
The proportional system was fairer than the previous first past the post model and resulted in far more diverse representation, better reflecting the make-up of the country, he said.
The electoral referendum was the result of two political failures -- the ineffectual Hunt committee report into MMP under Helen Clark's government in 2000 and National's "dubious" reasons.
"Nine years in the wilderness led them to question their chances to succeed under MMP."
Dr Johansson said apart from representation, the stability of the system was at risk. He painted a picture of constant change and ongoing referenda after each new model was adopted.
However, he did support the time period for any change. Under the bill voters in the 2011 general election will be asked whether they wanted to retain MMP and secondly which alternative system they would prefer from a list of options.
If a majority wanted change, another referendum would be held at the same time as the 2014 general election when MMP would be run off against the preferred option from the first referendum.
If more than 50 percent of voters opted to retain MMP in the first referendum, the Electoral Commission would undertake a review to consider whether changes to it were needed.
Dr Johansson said the timeline allowed for cool deliberation.
He also suggested the referendum question be changed to include modifying MMP. Many people were concerned by the way an electorate MP who won a seat did not have to meet the 5 percent threshold that other parties did to get other MPs into Parliament.
Polls showed that the great majority of people wanted to retain MMP.
Dr Johansson and several other submitters who appeared, including the Green Party, said there should be a limit on what could be spent on advertising.
Maori Party President Professor Whatarangi Winiata told MPs that referenda were not a good way of accessing Maori views and Maori institutions like marae needed to be used more. He said Maori should speak to Maori, the rest of the country speak to each other then a "distillation" of the two reached.