Prime Minister John Key has called Labour leader David Cunliffe an "idiot" over his comments about Kiwis' entitlements in Australia.
The Labour leader criticised Mr Key last week for doing little to advance New Zealanders' entitlements to the likes of student loans and social security benefits.
He also accused Mr Key of not negotiating hard enough on the issue of New Zealand-made products being excluded from Australian supermarkets.
The comments came ahead of Mr Key's high-level meeting with Australian Prime Minister Tony Abbott last week.
Responding to Mr Cunliffe on Newstalk ZB this morning, Mr Key said: "What an idiot. I'm sorry, but I mean, the guy goes in there and says 'Why don't you get better rights for New Zealanders?' forgetting he was part of the government that signed New Zealand up for this."