The shortened term could come about as a result of the Local Government Commission's review of Northland's council structure. It was prompted by the Far North District Council's application to form a unitary authority taking over the functions of the current district and regional councils.
The commission is now considering the application, as well as feedback from public meetings, iwi and other councils, before deciding on the future shape of local government in Northland.
If the commission opts for a new system, mayors and councillors elected on October 12 will be in charge only until fresh elections can be organised under a new local government structure, probably in late 2015.
That would put Northland out of sync with the rest of the country so the next election would be delayed until October 2019 to bring the region back into step.
The result would be a two-year term followed by a four-year term before Northland returned to the standard three years.
The problem for the current crop of candidates is that no one is sure what the commission will decide. It is expected to release its proposal in February.
The commission's options include the status quo, two unitary authorities based on the current Far North and Whangarei/Kaipara boundaries (as favoured by the Far North and Whangarei district councils) or a single unitary authority covering all of Northland. The Northland Regional Council wants a single authority but with seven genuinely empowered local boards. That, however, would require a law change.
If the commission opts for the status quo, the new mayors and councillors will serve a normal three-year term.
A possible shortened term for incoming councils appears to be reasonably well understood by candidates in the Far North District Council elections but has come as a surprise to some Whangarei councillors and candidates.
Local Government Commission chief executive Donald Riezebos said if the commission decided a new council should be set up before the date for the next three-yearly elections, existing councillors would have a shorter term and the next council would have a longer term. However, the Local Electoral Act stated that a "longer" term for a new council cannot be more than four years, he said.