On provisional results he polled 12,034 votes, 7110 ahead of his nearest rival, former councillor Lindsay Dow.
In what has become an election day tradition, Mr Shadbolt (66) based himself at the Invercargill City Council offices today and hosted lunch and drinks for successful candidates.
Between fielding a constant stream of congratulatory telephone calls, he said he was delighted to know people had so much confidence in him, especially considering he did not run an election campaign at all.
" I didn't have a single billboard up. I felt that after 18 years they [voters] must know who I am.''
Former policeman and Southland District Council staff member Gary Tong has won the three-way contest for the Southland District Council mayoralty.
Mr Tong, who owns and runs a holiday park of the outskirts of Invercargill, has not been an elected member of the council before but on the provisional talley headed off sitting councillors Paul Duffy and John Douglas with a majority of 180 votes.
Central Otago mayor Tony Lepper has been re-elected, and Gary Kircher will lead the Waitaki district.
It was a two-horse race for Central Otago's mayoralty, and preliminary results show Mr Lepper garnered 4416 votes, while Lynley Claridge drew 2521.
The results show Neil Gillespie (1511 votes), Nigel McKinlay (1205) and Shirley Calvert (1131) will be elected in the Cromwell ward, while Clair Higginson (860) and Malcolm Topliss (677) will be elected for the Earnsleugh-Manuherikia ward.
Martin McPherson (1673), Barrie Wills (1358) and Stephen Battrick (1152) are to be elected for the Alexandra ward, and Duncan Stuart (448) will represent the Maniototo ward on council.
Stephen Jeffery was elected unopposed for the Teviot Valley ward.
The final voting return for the district was 51.3%.
The final result is expected to be declared on Wednesday.
Gary Kircher has been elected mayor of the Waitaki District, beating nearest rival Jim Hopkins by about 400 votes.
Preliminary results show Mr Kircher drew 3087 votes, and Jim Hopkins got 2691. Eric Spittal (1024 votes) was the only other candidate in the six-way race to break 1000 votes.
Jim Hopkins (3309 votes), Hugh Perkins (3159), Melanie Tavendale (2996), Sally Hope (2932), Peter Garvan (2721) and Colin Wollstein (2648) will represent the Oamaru ward, while Kathy Dennison (583) won the right to represent the Waihemo ward.
William Kingan (906) and Sharyn Price (572) will represent the Corriedale ward.
The voter return rate was 55.43%.
