So, I think some of the shine might be coming off the Opportunity Party. Helen Clark has taken to social media and described the leader's interview on Q+A on TVNZ as a "train wreck".

She said: "Simplistic responses trying to defend land tax, higher income tax, job cuts in the public sector. Fantasy posing as policy."

Now, if you haven't seen the interview, Helen Clark is right, it was pretty bad. I probably wouldn't go as far as saying it was train-wreck bad but it was far from good.

The leader, Qiulae Wong, was flippant about people being as much as $17,000 worse off in extra tax under her policies. She basically said they just need to look at the bigger picture.

And she didn't know that the party's governing board has the power to veto caucus decisions, which is quite significant in terms of its impact on democracy.

This is actually shaping up to be one of her problems. She's rubbish at the details of her own policy. She's done the same thing when she's been on Newstalk ZB Drive. She came on to talk about their plan to forgive some of the cost of student loans for Kiwis who come home but she didn't know how much would be forgiven on average and she couldn't remember the total cost of the policy.

She is personable, she's likeable and she's a good talker. But her lack of knowledge about her own policies is going to hurt the party's credibility if this continues.

And this is why I think the Opportunity Party may have peaked too soon with that 8 percent result in one of the 1News polls. Had that come out maybe three or four weeks before an election, it might not have left enough time for people to discover all the details: how much extra tax they would have to pay and how nice but unprepared the leader is.

But this is 11 and a half weeks out. That's a long time for the screws to be tightened on this party and from both sides too: National and Labour, including Labour's Auntie Helen.

I would not be surprised if 8 percent proves to be their peak, especially if the leader doesn't brush up on her own policies.

LISTEN ABOVE