Simon Bridges accidentally referred to his second in command Paula Bennett as 'Paula Benefit'.
The nickname 'Paula Benefit' - or the variation 'Pullya Benefit' - has been used on Ms Bennett since her time as Minister of Social Development.
During her tenure, Ms Bennett oversaw a crackdown on welfare, including requirements for single mothers to return to work or face sanctions, and sanctions for those who don't meet drug and alcohol work test requirements.
Mr Bridges made the gaffe when he was asked about Mr Peters' claim the Government is polling well.
"Winston Peters spends a huge amount of time on me, on Paula Ben- Benefit- Bennett," Bridges said. "Let's start that again," he laughed.
"The reality is, he has not spent enough time as leader of our country as the Acting Prime Minister on things that matter to New Zealanders," Mr Bridges continued.