We can vote now, so why no election advertising on the polling day?

The two MPs vying to be Prime Minister have disagreed on whether election advertising should remain banned on election day.

After the 2017 election, the Electoral Commission encouraged the government to reconsider the law, which bans displaying, delivering, wearing or distributing campaign material.

You also cannot post on social media or websites, but you can adorn yourself or your vehicle with party colours.

With so many people casting their vote before election day, amid hordes of hoardings, Checkpoint's Nick Truebridge investigated why the law exists and whether people think it is time to move on.

There are many 19^th century traditions that have been scrapped from New Zealand law, like public executions, confiscating women's property and prosecuting non-believers.

But there is one strange tradition that lives on.

It is, as Otago University law professor Andrew Geddis puts it, that church-like law protecting the Kiwi conscience from political preaching on voting day.

"The rule itself goes back to the Victorian era. Elections, when they were first introduced, were a lot of pomp and ceremony. Candidates would process down to the polling places with all their supporters, big parades, brass bands, all that sort of thing."

That was thought to be inappropriate in the Victorian era, Professor Geddis said, and it was considered a solemn occasion.

"So this law was brought in… to try and make people be more solemn and take voting more seriously. And it's just carried on in New Zealand, it's become part of our political culture."

But what is the point of this Dickensian decree when 478,860 New Zealanders had cast an early vote by  the end of October 8, while campaigning remains in overdrive?

The law as it stands says campaigning can continue all the way up until October 17, polling day itself.

Come that day, no one - politician or member of the public - can do anything that might influence voters.

"With the growth of advance voting however it doesn't make a whole lot of sense because at least half, probably more than half this election, of the votes will have been cast while everybody's in the full swing of the campaign," Professor Geddis said.

"So having this one day at the end – some people still like it, some still value it as an experience – but in terms of its actual effect on the campaign and so on, it's hard to see why you'd have one rule for that one day that's different from all the others."

What do our potential Prime Ministers think? Is it time to let campaigning continue on voting day itself?

Labour leader Jacinda Ardern said it may be time to abandon the sabbath-like ban.

"Some of the things that were preserved for only on election day… the old rule that said you couldn't enrol on election day but you could enrol on every other day and vote at the same time.

So we have been progressively work through those issues. I think we still have to make sure though that we keep people free, unfettered when they access polling places, simple things like that need to be preserved.

"But maybe it is time with advanced voting so popular, to think about those other issues," Ardern said.

National leader Judith Collins wants to see the enshrined rule remain.

"Look I'm sure that one day we might well move towards an Australian model where people are stuffing pamphlets in people's hands as they're moving into the polling booth, I'd like to think not.

"I think there's got to be some decorum on election day and for a lot of New Zealanders they will vote on election day - there's a lot of undecided voters out there and what they're telling us all is that they haven't made up their minds yet."

The reality is most Kiwis will vote this election while campaigning is in full flight.

Advance voting numbers are expected to reach their highest levels. In 2017 47 percent of votes were cast early. That's expected to rise to about 60 percent this time.

In Auckland Central, voters who spoke to Checkpoint were split on whether earlier was better.

But there was widespread support for allowing political advertising to continue on election day.

Meanwhile, the Electoral Commission says it raised the inconsistencies between campaign rules during advance voting and the rules for polling day itself after the 2017 general election.

The Commission went a step further, saying the rules do need reconsideration.

So, what would it take to exile this rule introduced during Queen Victoria's 64-year reign? Here's Andrew Geddis.

"You'd have to get rid of the offence provisions in the Electoral Act that say that it's an offence to do any sort of campaigning on polling day itself. This has been looked at by select committees in the past and every time it comes up select committee basically says, 'New Zealanders just really seem to like this one day at the end of everything where there's a bit of peace and quiet, and all the campaigning stops."

For now though this centuries' old decree is here to stay, for this election anyway.

Break this 19th century edict? Well your fate won't be a Victorian-style hanging, but the Crown could levy a fine of up to $20,000.