Peter Dunne says he's not surprised over the recent controversy surrounding New Zealand First.
The party faces allegations that it failed to declare large donations, and hid the money in a secret fund.
Winston Peters says nothing illegal has occurred, but Dunne says he has seen similar allegations a number of times during his time in politics.
"It's the same sort of behaviour that we saw with the 1996-98 coalition that eventually led to New Zealand First being sacked from that," Dunne told The AM Show on Wednesday morning.
"It's the same behaviour we saw over the Owen Glen affair, which led to Helen Clark suspending Winston Peters and the party being voted out of Parliament in 2008.
"Leopards don't change their spots, I'm not at all surprised that this has occurred," the former politician said.
"It's about that time in the electoral cycle where things always go wrong for New Zealand First."
Dunne says he believes the public's patience is wearing thin.
"There's always been a vote out there for the anti-party, the party that's against everybody, standing up for the little New Zealander."
"But I think that those days are starting to wane and I think what you're seeing is firstly an increasing desperation to get those people back in the tent."
Dunne also believes there is some jostling going on for leadership of the party.
"You're seeing what looks like a leadership contest lining up with Shane Jones, who is pushing himself more and more into the forefront as hardly 'mini-me' but sort of 'I'm Winston's replacement, wait for me to come along'."
Prime Minister Jacinda Ardern has also faced criticism over failing to speak out over the allegations. On Tuesday she said the matter was something for the Electoral Commission to determine, not her.
"Winston Peters won't talk about it… and then you have got a situation where the Prime Minister is trying to wash her hands of this. She can't," Opposition leader Simon Bridges told The AM Show on Wednesday.
"It goes to the heart of her Government's integrity and the party that props up the Government. She needs to lead on it and she needs to ensure there is a full independent investigation going on."
Dunne says the fact that Ardern won't be drawn into the controversy shows the sway New Zealand First holds.
"It suggests that New Zealand First does hold all the power, does play all the cards. I think that's the problem that Labour's got in all of this," said Dunne.
"They can't control the situation, it's going from bad to worse in the public mind as far as New Zealand First appears, and that's going to start dragging the Government down with it."
Labour were both "tarnished" by Peters' party while also relying on them to govern, he said.
"It's a very difficult position to be in."
