The Prime Minister says he does not think it would be fair to retrospectively remove entitlements enjoyed by former MPs.
The Government has had to ditch a change to the way international travel perks are calculated for former MPs.
Former MPs elected before 1999, are funded the cost of a return trip from Auckland to London annually, using the lowest-cost online business-class return airfare.
A law change, that would have been voted on this week, would have linked that subsidy to a relevant Air New Zealand fare.
The Green Party says it cannot support the change because it would almost have certainly increased the cost to taxpayers.
The Transport Minister has said it would not go ahead if one party was to pull its support.
John Key was asked if there should be a wholesale review of MPs' perks, but said he did not think so.
"They're pretty well established, you can see that the authority is moving benefits away from non-cash to cash items.
"If you're asking about former MPs perks, it's really worth remembering that essentially we've come in New Zealand, not just in terms of MPs salaries but actually in the private sector as well, from a situation where people used to receive less cash and more benefits.
"We of course could just take those benefits off former and old MPs but we'd be doing that retrospectively; they would argue very strongly, and do, that we'd be taking away some of their entitled income because they were paid less as a result of it.
"I think it's just bad practice generally to go back retrospectively."
He said there would come a time when there were no former MPs able to claim these entitlements, because it only related to MPs elected before 1999.
Meanwhile, Mr Key said the Government intended to introduce the legislation reducing current MPs salaries to Parliament this week.