A New Plymouth lake is being drained in an effort to stop invasive clams.

Lake Rotomanu's been closed to motorised watercraft since the gold clams were found there last month, marking the first discovery of the species outside of the Waikato River.

The lake's outlet was opened yesterday, and it will take about four days to drain completely.

Dave Cade told Kerre Woodham it’s the worst biosecurity threat to New Zealand’s freshwater that the country’s ever faced.

He says the clams reproduce asexually, and they’ll smother the bottom of lakes, smothering native organisms and clogging hydro stations.

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Nicola Willis is defending her economic track record in the face of a lobby-group's satirical campaign.

The Taxpayers' Union has sent MPs Nicola Willis-branded fudge, claiming she favours treats today and taxes tomorrow.

It suggests Willis should cut spending more.

Willis says the Government has reduced taxes and delivered significant cost savings while keeping frontline services.

Kiwiblog author and co-founder of the Taxpayers' Union, David Farrar told Kerre Woodham that putting aside personalities, it’s not a bad thing for people to realise we still have a real fiscal challenge in New Zealand.

He says that while the Government has cut spending in a number of areas, we’re still spending more than we’re bringing in in taxes.

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Do you see any advantage or benefit to the country in having a former Finance Minister and the current one debating fiscal policy?

The current Finance Minister, Nicola Willis, has challenged the former Finance Minister, Ruth Richardson, to a debate. Now, that is misguided in my view, but to be fair, she was grievously provoked. Ruth Richardson is the chair of the Taxpayers' Union. The Taxpayers' Union is a pressure group, a ginger group, founded in 2013 to scrutinise government spending, publicise government waste, and promote an efficient tax system.

Its basis is its membership is mainly conservative, centre-right, right-wing figures, and it's regarded as a right-wing pressure group. Normally you would think they'd be scrutinising Labour and Labour's spending. Last week, the Taxpayers' Union sent out a provocative pamphlet and an accompanying box of fudge, accusing Nicola Willis of not delivering on her election promises to rein in reckless spending, unsustainable borrowing, and the hiring of endless bureaucrats. The Union accused Willis of failing to deliver the goods and fudging it, hence the fudge that arrived with the press release.

Provoked and incensed beyond reason, Nicola Willis swiped back. She said, "My message for Ruth Richardson is a very clear one: come and debate me face-to-face, come out of the shadows. I will argue toe-to-toe on the prescription that our government is following. I reject your approach, and instead of lurking in the shadows with secretly funded ads in the paper, come and debate me right here in Parliament. 'm ready anytime, anywhere, I will debate her." So you can see she was a little bit brassed off.

Willis said she stood by her decisions in government and wanted Richardson to defend her legacy, having introduced the infamous Mother of All Budgets in 1991, when her government under Bolger came in and were left with, I would argue, an even worse fiscal mess than this government inherited.

It's all got very personal. I don't think there's anything wrong in critiquing decisions made by government ministers, looking at how they're going, giving updates, having a reckon, especially when the ministers came in on a campaign of fixing the economy and reining in irresponsible spending, it's fair enough to say, "Okay, have you?" The Coalition Government possibly hasn't done enough, been innovative enough to suit the Taxpayers' Union agenda. They wanted more. They wanted cuts in spending, they wanted slashing of and wholesale firing of bureaucrats. That's what they wanted, but the Government's in the tricky position of having to be responsible stewards of the public purse and get re-elected.

And that's a tricky one. The Taxpayers' Union doesn't have to worry about getting elected. It's a stand-alone lobby group. The Taxpayers' Union has criticised Nicola Willis for a measly 1% reduction in public servants, but as David Farrar from Kiwiblog points out, this may well be the first government in history to actually reduce the number of public servants. They're the first ones to have done it.

It was never going to be easy inheriting the situation left by the previous government, and it never is. The Labour governments spend, that's what they do. But there's also nothing wrong with critiquing the performance of the government. The Taxpayers' Union shouldn't have made it so personal. Nicola Willis should have showed superhuman restraint and not lashed back.

The debate is a pointless waste of time in my view. I know that we're all political tragics here and we take far more interest than the average person does and if I thought there was any merit whatsoever, and if lessons could be learned or if as a country we would benefit from having these two Finance Ministers thrashing out points of economic order, fine. I just don't see it. I think it's egos have been wounded and it is the equivalent of challenging somebody to 50 press-ups – a pointless exercise. Just because you can, doesn't mean you should.

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