The Make It 16 campaign is in court this week, arguing that the voting age is unjustifiably discriminatory and breaches the Bill of Rights Act. I think that is pushing shit uphill - the BORA hard-codes the age-limit (just as it hard codes 16 years as the age over which discrimination is de facto unjustifiable), so they're effectively asking the court to find the BORA inconsistent with itself. But in some ways the point isn't to win, but to make the argument, in one of the most public forums available. And if the court says "yes, its shit, but we can't", then that's a victory because it places implicit pressure on the government to fix it. Not that fixing it is easy: the Electoral Act clauses governing the voting age are entrenched, meaning that reform requires either a 75% majority in Parliament, or a referendum. But I think the government has a moral obligation to make the effort.
The arguments in favour of lowering the voting age are compelling. There is simply no moral argument for excluding people old enough to express their interests from voting, and you cannot call yourself a democrat if you think there is. There are also significant turnout benefits, with a better chance of building a lifelong habit of voting if you start younger. And for those who think that young people are too frivolous, irresponsible or uneducated to vote, maybe they should be looking at Boomers...