Prime Minister John Key is warning MPs to behave following what he describes as "a nasty streak" running through Parliament.
Earlier this week, the bad blood between the New Zealand First leader and his former MP spilled over in the House, with Winston Peters calling Brendan Horan the "Jimmy Savile of New Zealand politics".
The late Jimmy Savile is a disgraced former BBC television presenter.
The independent MP objected to Mr Peters' comments, saying he found them disgusting. After being ordered by the Speaker David Carter, Mr Peters withdrew the comment and apologised.
The Speaker has also ordered an inquiry into MPs use of social media after tweets critical of his performance in the House and one made by a Green MP.
In a tweet last week, Jan Logie used an expletive while referring to Finance Minister Bill English's six children and six Budgets. She later said she regretted the tweet and offered to personally apologise to the minister.
Mr English said he was not offended, but that it revealed the nasty side to the Greens.
Mr Key said on Thursday that politicians risk offending the public with nasty behaviour or mindless tweets.
"Political parties actually need to think about that a little bit. We're seeing tweets that I think have been wholly inappropriate, we've seen all sorts of allegations been made that are unfounded.
"It's one thing to have parliamentary privilege - it's quite another thing to actually say those things, because actually they do have repercussions, they do send ripples through the community."
Mr Key said a tweet is no different from a media statement.