City councillor and mayoral candidate Lee Vandervis brought the house down - in all the wrong ways - at the first of Dunedin's mayoral debates today.

The event, at the University of Otago's main common room, was organised by the Otago University Students' Association and watched by a crowd of about 130 mainly younger students.

But, when candidates were asked what they would do to engage with the youth voice and increase voter turnout among students, Cr Vandervis bucked the trend by saying he did not want to see more younger voters.

"They don't know enough about candidates. They don't care enough about candidates,'' he told the audience.

Instead, it was better to focus on having "educated'' voters, he said, as members of the audience reacted.

"Sit down,'' one yelled.

"What about our democratic rights?'' shouted another.

The debate attracted 13 of Dunedin's 14 mayoral candidates, as only Cr Andrew Whiley was unable to attend.

Candidates were asked a range of questions - including on climate change, student housing, transport and the Te Tiriti o Waitangi - before being invited to give a closing statement.

Time limits were strictly enforced, given the size of the field, but a unofficial straw poll after the forum - using jars and tokens - showed strong support for Green Party candidate Aaron Hawkins.

However, there was late controversy - of sorts - when fellow candidate Malcolm Moncrief-Spittle discovered his name had been left off his otherwise empty jar.