ACT leader John Banks is the only MP who has serious problems with the Electoral Commission's proposed changes to MMP.
The commission on Monday released its proposals after a six-month review of the voting system.
It says the threshold to get into parliament should be lowered from 5 per cent to 4 per cent of the party vote.
And it wants the "coat tails" rule that allows those who win an electorate seat to bring in extra MPs without reaching the threshold abolished.
Labour and the Greens are welcoming the proposals but Mr Banks says he won't support them.
He is scathing about the proposal to abolish the one seat threshold rule - which he relied on to win his seat last year - and says the commission's argument for abolishing it is "woeful".
The commission says most of the more than 4700 public submissions it received opposed the rule and its own opinion is that it is unfair.
National supported Mr Banks in Epsom in the last election, hoping that by winning the seat he would bring extra MPs into parliament and it would have a strong support party to rely on.
It didn't work because ACT won only 1 per cent of the party vote and that wasn't enough for more MPS, and the change makes it unlikely National will again protect Mr Banks in 2014.
Labour's Lianne Dalziel says the commission's proposals were well-considered.
"Everyone wants to see an end to political stitch-ups and canning this clause will stop dodgy deals," she said.
The Greens say lowering the threshold will avoid wasted votes and the party is praising the commission's "underlying principles of fairness".
NZ First says the threshold should stay at 5 per cent and the commission should have dealt with "serious issues" like the number of seats in parliament and the rules around donations.
Those issues weren't within the commission's terms of reference.
The government isn't taking a position on the proposals, which are open for public submissions before the commission presents its final report to Justice Minister Judith Collins at the end of October.
Then it will be up to parliament, because law changes are going to be needed to implement the proposals before the 2014 election.