Prime Minister John Key was bailed up by an Act Party member angry that National was not sticking to its side of a "deal" between the two parties.
Morris Hey, Act's electorate chair in New Plymouth, approached Mr Key at a New Plymouth mall today.
He said Act had agreed not to stand in New Plymouth to help National hold the seat.
However National was failing to do its part by withdrawing its candidate from Epsom.
Mr Key told Mr Hey to talk to his own party about the issue, and quickly moved on.