The Government's response to a review of MMP is due today.
The Electoral Commission delivered a report to Justice Minister Judith Collins last week, and her response will go before Cabinet and the Government will release it this afternoon.
Prime Minister John Key told Radio Live today a bill would have to go through Parliament for changes to be agreed.
"The question is will there be changes? If so; what, and will there be Parliamentary support for it?"
Mr Key said if there is no Parliamentary support for the recommendations, it wouldn't progress.
A number of changes were proposed to MMP following the Electoral Commission's comprehensive review of the system.
It looked at a number of issues: including the five per cent and one electorate seat thresholds, the ability to stand in an electorate and be on the party list, and whether a list MP can stand in a by-election.
Final proposed changes are:
• The party vote threshold for the allocation of list seats should be lowered to four per cent.
• The one electorate seat threshold for the allocation of list seats should be abolished.
• The provision for overhang seats should be abolished for parties that do not cross the vote threshold.
• Candidates should continue to be able to stand in both an electorate and on a party list at general elections.
• List MPs should continue to contest by-elections.
• Political parties should continue to have responsibility for the composition and ranking of candidates on their party lists.
Mr Key said he didn't have a strong view on the proposed changes.
"The National Party's view has been not to support those changes," he told Radio Live this morning.
He said some of the changes could lead to more volatility.