Labour leader Andrew Little says "well-paid PR operatives" are part of the "vicious" online commentary which he said could be contributing to threats against Government ministers.
Mr Little said today that a change in the tone of online communications, combined with tough economic conditions, were factors in the recent behaviour by members of the public towards Social Housing Minister Paula Bennett and other MPs.
• Paula Bennett receives death threats
He stressed that he was not condoning threats against MPs, but that he had observed a "palpable" difference in anger from New Zealanders compared to a year ago.
Mrs Bennett has been threatened on several occasions in the last two weeks.
In one instance, the minister complained to the police after a Facebook user said someone should "shoot the b**** dead" at her next public appearance.
Asked what was behind the threats to MPs, Mr Little said this afternoon that some New Zealanders were in a worse position compared to a year ago and were feeling less confident about the future.
"It's not a justification for aggressive behaviour or even aggressive comments. But if you combine a sense that people are feeling that life is tougher along with this change in the tone of a lot of communications -- some of which are coming from well-paid PR operatives too I might add -- then it's not surprising that there are some people who are going to read completely the wrong signal and think that it's OK to make completely unacceptable comments."
Mr Little appeared to single out lobbyist Matthew Hooton.
Asked by a reporter whether he was referring to Mr Hooton, he said "Could be". He said the lobbyist had "a particularly vicious ... edge to his communications".
Mr Little said he could not cite specific communications off the top of his head.
"They have an edge to them, that is, I think, unfitting of somebody who claims to be a disinterested observer with right-wing leanings."
Mr Hooton is a former National Party press secretary and is now an outspoken right-wing political commentator.
Asked to respond to Mr Little's comments, Mr Hooton said the Labour leader was "an idiot" and he had "no idea" what he was referring to.
"I can't think of anything that could be characterised as vicious over the last 12 months or so," he said.
"I should probably seek an apology ... but I don't think he's a person worth seeking an apology from."