The National Party is rejecting calls from youth to lower the voting age to 16.

A new campaign, Make it 16, has been launched in the wake of this year's Youth Parliament, which saw teenagers take over the House for two days.

"Make it 16 is a non-partisan, youth-led campaign advocating for more people's voices to count in our democracy," said spokesperson Oli Morphew, 14.

"People who are 16 can work full-time, consent to sex, drive a car, and own guns," said 17-year-old Molly Doyle, who stood in for James Shaw last week. "They should also be able to vote."

Even the youth MP for pensioner-friendly Winston Peters, 17-year-old Ethan Nemeroff, is keen.

"Young people need a greater voice because the long-term issues facing New Zealand are most going to affect us."

Children's Commissioner Andrew Becroft is in their corner, saying the school climate protests in May showed many teenagers are quite capable of understanding complex issues and having their say.

In some ways, they may even be ahead of their adults - the Youth Parliament passed a resolution declaring a climate emergency. RNZ reported the motion, from Chloe Swarbrick's Youth MP Luke Wijohn, was met with a "swift, rousing chorus of ayes and scattered noes". Swarbrick's own motion in the real Parliament, which she tried to pass "without motion and without debate" in May, was shut down by National.