Age is just a number for a group of teenagers arguing to lower the voting age.

Arguments are underway in the High Court at Wellington to decide whether the voting age is discriminatory.

They say the current age of 18 is inconsistent with the Bill of Rights Act.

Lawyer for Make it 16 Jason McHerron says international law doesn’t back restricting voting to those over 18.

If anything, he argues it supports lowering the age.

McHerron says the royal commission found the only justification for excluding people from voting is competence – so 18 is probably too old.

17-year-old Julia Randerson says people who dismiss the idea of a lower voting age don't recognise how politically engaged youth can be.

"There's always going to be a small amount of people in every age group who aren't engaged in politics, but we don't see it to be any lower in 16 and 17 year olds than it is in any other age group."

Isobel Smith told Kerre McIvor that 16 and 17 year olds tend to be more settled in their lives, living at home rather than at university or flatting. 

"In Scotland and Austria, where the voting age is 16, there is a higher voter turnout among 16 and 17 year olds than those in their 20s."

The case outcome will not impact this election.