Dunedin city councillor Dave Cull appears to be leading a two-horse race with Mayor Peter Chin in the battle for the city's top job.
An Otago Daily Times poll of voters who had made a decision shows Cr Cull ahead on 45.9%, Mr Chin second on 37.4%, and Lee Vandervis third on 11%.
None of the other four candidates had made it over 4%, although there were still plenty of undecided voters, at 38%, two weeks before the end of the polling period.
In the raw data, the 274 respondents who said they were undecided outstripped votes for any candidate.
The poll of 721 people was undertaken by ODT staff over a four-day period this week.
University of Otago political studies department lecturers Dr Chris Rudd and Associate Prof Janine Hayward studied the figures, and said this year's election was clearly a "quite different" race from 2007, when Mr Chin led in a similar poll with 72% of the vote.
The closeness of Cr Cull and Mr Chin's polling should encourage people to return their voting papers, she said.
It should also bring the single transferable voting (STV) system into play, with voters' second preferences likely to make a difference.
Only 10.9% of voting papers had been returned last night, and the key message to voters yet to do so was "you can have an influence", Prof Hayward said.
That Cr Cull and Mr Chin were well ahead should not put off people who supported other candidates as their first preference, as their second preferences would help decide who would become mayor.
"They should stick to their guns about who their first preferences are, as long as they rank more than one preference."
One aspect of the Otago Daily Times poll was that 721 people said they would vote, while about 150 said they would not.
That meant around 80% were stating they would vote, when the actual percentage at the last election was only 47.4%.
Cr Cull said while he did not know how the election was panning out, he had been getting "some very positive feedback".
"It's a very positive start," he said, though he noted there was plenty of time to go before the end of the election.
"I'm very pleased with that news," he said, referring to the poll.
Mr Chin said it was still early in the election, and he had no major campaigning planned.
"I'll just keep on doing what I'm doing."
Mr Vandervis said mid-election surveys were illegal in some countries, as they "potentially give the media opportunities of skewing voting behaviour".
He said the ODT poll showed a "quite different result to our own surveying, as it did in the last election, when the ODT mayoral survey put me nowhere, with the also-rans, when I actually achieved a clear second place with 33% of Mayor Chin's vote".
He said his information showed a "significant swing to Vandervis", especially in the past week.
"The only survey that counts is the final vote, which I believe will show a much closer race."