The main reasons for not voting were similar to the 2008 election. Non-voters said they had other commitments, work commitments, they couldn't be bothered, couldn't decide who to vote for, or felt their vote wouldn't make a difference.
Mr Peden said he wasn't losing sleep over the 2011 election turnout, because it had been influenced by external factors such as an uneven election race. But he was very concerned about a long-term, steep decline in voter turnout since 1987.
"New Zealand used to be a world leader in turnout, we certainly aren't any more. If we want a healthy democracy we must reverse the trend."
The commission was taking some long-term initiatives, such as teaching the value of elections and the political process to Year 9 and 10 students.
Some political scientists said yesterday fines should be introduced to raise voter turnout. But asked if New Zealand should follow Australia and fine people for not voting, Mr Peden said the commission preferred the carrot to the stick.
He said despite the fines, which can range from A$20($25.52) to A$50($63.80), Australia's enrolment rate was worse than New Zealand's.
He also said online voting had not improved turnout in overseas trials.
University of Otago political lecturer Bryce Edwards said the trend of fewer voters was observed worldwide. "Our trend has been a bit steeper than other countries. We're not at the depths of the United States, but we're headed in that direction."
He was wary of blaming poor turnout on voters, because not voting was also a legitimate, intentional action.
"It should be embarrassing for politicians and political parties because they're the people that aren't having their product bought."
The survey was based on interviews with 1097 voters and 272 non-voters.
Stay-at-homers
Main reasons for not voting
* Other commitments - 14 per cent
* Work commitments - 9 per cent
* Couldn't be bothered voting - 14 per cent
* Couldn't work out who to vote for - 11 per cent
* Vote would not make a difference - 8 per cent
Factors that influence not voting
* 'I don't trust politicians' - 33 per cent
* 'It was obvious who would win so why bother' - 31 per cent
* 'I'm just not interested in politics' - 29 per cent.