A former leader of the Green Party, Jeanette Fitzsimons, says she was "deeply distressed " her party supported the so-called waka jumping bill to its first reading and she hopes wisdom will prevail.
She spoke about the internal dissent and crisis within the Green Party before the last election over the admission by co-leader Metiria Turei of historic benefit fraud.
She appeared before the justice select committee to speak against the Electoral (Integrity) Amendment Bill, which allows a party leader to oust an MP from Parliament with the support of two thirds of the caucus.
"Dissent is a valuable part of the political process, " she said. "Without it, MPs are just clones of their leader."
Referring to the Greens' internal strife before the last election when MPs Kennedy Graham and David Clendon withdrew from the party list because they could not persuade Turei to resign, she said she supported their right to dissent.
"I strongly disagreed with the stance of my former colleagues Kennedy Graham and David Clendon took on the actions of co-leader Metiria Turei, and I was highly critical of the way they went about it which was unnecessary and damaging.
"But I would defend to the end their right to freedom of conscience and to express their views in opposition to the rest of the caucus, without being thrown out of Parliament."
If the bill becomes law, the Greens co-leaders with the support of two thirds of the caucus, could have had them booted out of Parliament.
"Integrity cannot be legislated for," Fitzsimons said. "It is a matter of conscience and judgment.
"In some cases, leaving one's party is an act of integrity – as when the party has departed from the policies it took to the election or has abused proper process.
"In other cases it may be just self-serving political expediency."
Normally the law had the sense not to intervene. With a three-year term, voters did not have long to wait to judge the actions by generally returned MPs who changed allegiance on well-founded principles and getting rid of the opportunists.
Labour signed up to the bill as part of its confidence and supply agreement with New Zealand First but with National opposing it, the coalition needs the Green Party to pass it.