The National Party says it would be breathtakingly arrogant for the government to pass the waka-jumping legislation given the opposition to it in public submissions.
The legislation is being considered by the Justice Select Committee, which is hearing submissions at Parliament.
National's Nick Smith, who sits on the select committee, said all of the submissions the committee received were against the legislation.
He said that was no surprise as the bill would be a significant change to electoral law.
"The major concern is giving the power of party leaders to be able to dismiss an MP and effectively a transfer of power to party leader at the expense of MPs and voters."
The legislation includes a provision where a leader must get the support of two-thirds of the party's caucus to eject an MP.
But Mr Smith said if a leader proposed to get rid of an MP and could not get two-thirds majority in caucus that would effectively be a vote of no confidence in the leader.
"If we think of any of the practical examples that have occurred in recent history, whether it was Marylin Waring with Rob Muldoon, whether is was Tariana Turia with respect to the Foreshore and Seabed issue and Helen Clark, there is no question that the leader would be easily able to get the caucus majority of two-thirds to dismiss that MP."
The former Green Party co-leader, Jeanette Fitzsimons, said she voted against the same legislation four times when she was in Parliament and she could not believe it has reared its head again.
She said it was up to voters to decide who should be in Parliament, not other MPs.
"Voters have made that judgement very well, when you look at the people who have been re-elected after leaving their party and had a principled reason for doing so, and those who have been cast into the wilderness, voters have generally got it right."
The bill is part of the coalition deal between Labour and New Zealand First, but made it through its first reading with the support of the Greens as well.
Green Party members have voiced their upset at parliamentary wing's decision to vote for the bill, and its leader, James Shaw has told RNZ it will wait until the select committee reports back before it decides to support it further.
Ms Fitzsimons said she hopes the Greens will hear what is being said at select committee and do the right thing.
"There's nothing in the agreement between the Green Party and the Labour Party which requires the Green Party to vote for this bill, it's all about the interpretation of good faith.
"I don't believe that the government will fall on this issue."
The committee is continuing to hear submissions and is due to report back to Parliament at the end of July.