The mayors of the Queenstown Lakes District and Central Otago have both won second terms.
Vanessa van Uden's Queenstown win comes despite angry protests at the way she has run her mayoralty from a faction of Wanaka residents, who say she favours Queenstown.
Those residents advocated invalidating their voting forms and preliminary votes counted show more than 800 were either invalidated or left blank.
Ms Van Uden disputes the view that Wanaka is not well represented, and says residents "get their fair share."
"I think we've spent a lot of time and effort and energy over the last three years working on Wanaka issues and trying to improve things over there."
Ms van Uden has a tough term ahead as she tries to secure funding for a $50 million convention centre in Queenstown, with ratepayers saying they don't want to pay for it.
In Central Otago, Tony Lepper last term unseated long-serving mayor Malcolm MacPherson and this time staved off a challenge from Lynley Claridge.
During his second term he will need to tackle the growing problem of water availability, for both domestic town supply and farm irrigation, in the arid Central Otago district.
Elsewhere in the South Island, Waimate has a new mayor, with one-term councillor Craig Rowley beating fellow councillor Sharyn Cain. Previous mayor, John Coles, did not contest the election and has now retired.
At least four other South Island mayors were elected unopposed - David Ayers for Waimakariri District, Winton Dalley for Hurunui District, Tracy Hicks in Gore District and Grey District's Tony Kokshoorn.
In Ashburton, Angus McKay won a second term as mayor by a comfortable margin over nearest rival Russell Ellis and Kaikoura mayor Winston Gray was also re-elected, seeing off a challenge from Darlene Morgan.