Generation Game: Latest poll shows election outcome could be down to how many young people vote

National 41.9 per cent, Labour 41.6 per cent.

That's Radio New Zealand's latest poll of polls, and it shows how vital voter turnout is going to be on Saturday.

Complacency would be fatal for National, as would a poor showing by young voters for Labour.

National has the edge because older voters have always turned out in greater numbers than the young ones. But the party has suffered from complacency in the past, something it can't afford this time.

In 2014 the Kim Dotcom fiasco energised National's supporters. Dotcom's attacks on the government and his "moment of truth" threats, which turned out to be nothing, motivated National's voters and got them to the ballot boxes.

After the election, the party figured Dotcom had been worth between one and two percentage points.

Compared with that, the campaign that is now in its final days has been relatively benign.

The farmer protests against Labour's proposed water tax is the closest thing to voter anger that's been seen, and the publicity around it could help National.

The rural vote mostly goes to National anyway but the folks in the provinces are likely to be more determined to make their views count than they would otherwise have been.

Labour leader Jacinda Ardern hasn't done herself any favours by putting out a water policy that lacks detail, and National is doing its best to inflame uncertainty.

"Only four days out from the election and Labour's leader still has no idea how much her planned water tax would cost," finance spokesman Steven Joyce said on Tuesday.

It isn't correct that she has "no idea" because she has said it could be one or two cents per 1000 litres but that, as has been pointed out, is a 100 per cent variance.

Labour says it needs time in government to nail down issues such as the water tax, which National doesn't accept.

"These people want to be running the country next week, it's simply not good enough," said Joyce.

Lack of policy detail has plagued Ardern throughout the campaign, but it hasn't affected her remarkable ability to get people on her side - particularly the younger ones. She's been party leader for just a few weeks and she's transformed Labour's political future from hopeless to neck-and-neck with National. And she appears to have achieved it largely by managing to generate political interest among younger voters.

Evidence of a potential "youthquake" was in the latest 1News Colmar Brunton poll, in which 67 per cent of 18 to 34-year-old respondents said they supported Labour.

National does better than Labour when the age range gets up into the 50-plus, and much better when it reaches 65-plus.

Because they've been around a long time, nearly all of the older voters are registered. That isn't the case with the younger ones, and up to a couple of days ago less than 70 per cent of the eligible 18 to 24-year-olds had enrolled.

When it comes to the crunch, older voters historically make an effort to get out and vote. Labour's chances of changing the government depend on the younger ones doing the same.

- NZN