Labour Party leader David Cunliffe has reminded his MPs about making comments outside their portfolio responsibilities, after remarks from Shane Jones about a Green Party MP.
Mr Jones criticised Gareth Hughes on Waatea News for interfering in an Environmental Protection Authority hearing into a plan to mine iron ore from the seabed.
Mr Jones said he tried not to interfere in the Commerce Commission's statutory responsibilites when raising concerns about supermarket chain Countdown.
He said that should also be "good enough for the Green mollyhawk" with the EPA.
The Greens did contact Labour at the time, and the comments will be discussed between the parties' chiefs of staff at their next meeting.
Mr Cunliffe says he has talked to the caucus about sticking to their portfolios and not attacking potential coalition partners.