The Prime Minister is ruling out getting rid of the coat-tailing rule of MMP before the general election.
Labour Party leader David Cunliffe has called on John Key to support its member's bill that would stop electorate MPs bringing list MPs into Parliament.
The call comes a week after the Internet-Mana alliance was formed.
Mr Cunliffe says a Labour-led government would initiate a law change within its first 100 days in office, if elected on 20 September.
But Mr Key said on Wednesday that National won't help get rid of the rule and called Mr Cunliffe hypocritical, as he's likely to need Internet-Mana if he is to form a government.
"If David Cunliffe really believes that, there's a very simple solution to this: he simply needs to rule out the Internet-Mana Party.
"He doesn't believe that they are legitimately entering Parliament after the 2014 election on the basis that they get enough votes or seats to get in. He should just rule them out."
The election will be held on 20 September.