Smith recently served on the Three Waters working party, set up to address growing nationwide councils' concerns over proposals for the restructuring's representation, governance and accountability.
He said he firmly rejected what the Government was proposing under the Three Waters restructuring.
Smith's decision to not seek re-election for the October local government elections means the tsunami of leadership change facing Northland is gathering pace.
Far North Mayor John Carter and Whangārei Mayor Sheryl Mai will not be seeking re-election. Northland Regional Council (NRC) chair Penny Smart said she was 'undecided' about standing again, last time approached by Local Democracy Reporting Northland. (The NRC chair is selected by fellow successful councillor candidates, in contrast to district councils where candidates stand for Mayoral positions).
Smith's move means there will be no incumbent mayors for the Government's proposed entity A Three Waters inter-regional body coverage area. Auckland Mayor Phil Goff has also announced he will not be seeking re-election.
Smith said seeking the National candidacy for Northland had become the best way to serve the people of Northland. The seat encompassed all of Kaipara and Far North district.
"If successful I would then contest the Northland electorate for the National Party in next year's general election. I want to win back the Northland seat for National and change the government," Smith said.
Smith said his first job, at 21, at the European Parliament in Luxembourg, had started a lifelong interest in politics, alongside his interest in farming on the family's 600-hectare Ruawai sheep and beef farm.
He said representing Kaipara people as Mayor since first being elected in 2018 had been a life's highlight.
Smith said he had made his decision to head towards national-level politics earlier this week.
"It is important that the people of Kaipara district know at the earliest moment, especially possible mayoral candidates for the council in the next term.
"Nominations for elected members of council close 10 weeks from now, on August 12.
"I will not contest two positions at the same time and risk the cost of a by-election for the Kaipara ratepayers if I were to be successful in the candidate election process later this year," Smith said.
Local Democracy Reporting is Public Interest Journalism funded through NZ On Air.