Key dates for the 2023 Port Waikato by-election.
| PORT WAIKATO BY-ELECTION TIMETABLE | |
| Tuesday 10 October | Port Waikato electorate by-election dates formally announced |
| Monday 16 October | Writ Day Governor General issues writ directing the Electoral Commission to hold the Port Waikato by-election |
| Tuesday 17 October | Start of the regulated period for election advertising expenses |
| Friday 20 October, noon | Nominations close for candidates in the Port Waikato by-election |
| Friday 20 October | Port Waikato by-election candidates announced by the Electoral Commission |
| Saturday 21 October | Ballot paper printing starts |
| Wednesday 8 November | Overseas voting starts Telephone dictation voting starts |
| Monday 13 November | Advance voting starts |
| Friday 24 November | All political advertising ceases and election signs taken down by midnight |
| Saturday 25 November | Election day for Port Waikato by-election Voting places open from 9am to 7pm |
| Saturday 25 November | Preliminary Results progressively available from 7pm on www.electionresults.govt.nz Targets for release are: by 9.00pm - results from 50% of voting places by 10.30pm - results from 95% of voting places These are targets not guarantees |
| Wednesday 6 December | Official Results declared (including special declaration and overseas votes) |
| Monday 11 December | Deadline for applications for judicial recount |
| Tuesday 12 December | Return of Writ by Electoral Commission naming successful candidate (presuming no recount) |
| Tuesday 26 March 2024 | Deadline for Returns of Candidate Election Expenses and Donations to Electoral Commission |