When is a private dinner attended by a Cabinet minister no longer a private dinner? When the taxpayer is meeting some of the cost - either directly or indirectly.
Or so argued Labour MPs in Parliament yesterday as they pressed Judith Collins once more to reveal the name of the senior Chinese border control official with whom she dined in Beijing last October along with her friend Stone Shi, the founder of the milk exporting company Oravida, of which her husband is a director.
The Justice Minister's perceived conflict of interest may have been last month's story. But Labour is continuing to ask questions about her China trip because it sits well with the party's attempt to portray National as hostage to "crony capitalism''.
Citing advice from the Prime Minister's office, Collins responded to Opposition questions by continuing to insist the dinner was a private affair and it was not appropriate to disclose the name of the official who was a friend of Mr Shi.
"He was attending a private dinner and is entitled to protection of his privacy.''