In Dunedin, Mayor Dave Cull fended off a challenge from eight rivals, led by former Act New Zealand MP Hilary Calvert and followed by incumbent Dunedin city councillor Lee Vandervis.
Mr Cull told the Otago Daily Times it was "really gratifying to get the confidence of the community reinforced''.
Further South, Invercargill Mayor Tim Shadbolt entered the record books after being reelected, becoming the city's - and New Zealand's - longest serving municipal mayor.
Provisional results showed he polled 12,034 votes, 7110 ahead of his nearest rival, former councillor Lindsay Dow.
Mr Shadbolt said he was delighted people had so much confidence in him, especially considering he did not run an election campaign.
"I didn't have a single billboard up. I felt that after 18 years they [voters] must know who I am.''
Voters also threw their support behind Queenstown Lakes District incumbent Vanessa van Uden, who won in a landslide over her only rival, Al Angus, of Glenorchy.
Preliminary results showed Ms van Uden (46) received 6056 of the votes, compared to Mr Angus' 1509.
Central Otago mayor Tony Lepper was also-reelected for a second term after receiving 4416 votes in the two-horse race with Lynley Claridge, who received 2521 votes, preliminary results showed.
Clutha District Mayor Bryan Cadogan was another incumbent returned, also for a second term, after scoring a clear majority of 4274 votes over his deputy mayor and challenger Hamish Anderson's 1463 votes.
The only major change in the south came in the Waitaki District, where Oamaru businessman Gary Kircher was set to replace two-term mayor Alex Familton, who decided not to seek re-election this year.
Mr Kircher, with 3087 votes, was leading the race between seven candidates with 98% of votes counted and less than 400 still to be added.
A result was yet to be officially declared, but Mr Kircher's closest rival, incumbent deputy mayor Jim Hopkins, with 2691 votes, has conceded defeat.
Elsewhere, Gore Mayor Tracy Hicks was reelected unopposed and Mackenzie District Mayor Claire Barlow won a second term, a result she said left her "quite humbled and really stoked''.
Former policeman and Southland District Council staff member Gary Tong won a three-way contest for the Southland District Council mayoralty, heading off sitting councillors Paul Duffy and John Douglas with a majority of 180 votes.
