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.