The link to the online entering webpage, which also has the Supplementary Regulations is via the new MotorSport Online website:
https://online.motorsport.org.nz/msnzprofile/login

Close off date for entries is 20th October 2023

In the words of all Event Secretaries everywhere: "Your early entry greatly assists the organising of this event".

Since most people on TRS probably won't have a log in to MotorSport Online, here are some handy snippets from the Supp Regs:
Friday 10th November 2023
8.00 am to 5:30 pm Documentation and Safety Audit at Manfeild Circuit Chris Amon
9.00 am Untimed Testing
12:30 pm approx. Lunch
1.30 pm to 5.30 pm Untimed Testing
Saturday 11th November 2023
7.00 am to 12 noon Documentation and Safety Audit at Manfeild Circuit Chris Amon
8.00 am Drivers briefing
8:15am New drivers briefing in the Control Tower.
8.30 am Qualifying
After Qualifying Racing starts
1.00 pm approx. Lunch time Demonstration runs
1.45 pm approx. Racing continues
Sunday 12th November 2023
8.30 am Racing starts
12.00 noon approx Lunch time rides for the Cancer Society / Kara Hands Charitable Trust and Hot Laps
12.45 pm approx Racing continues

Vehicle Classes:
Classics
Allcomers (including Schedule K and Group A Cars)
F5000
Historic Muscle and Saloon Cars
Historic Sports Sedans & Invited Allcomers
Historic Racing Cars, Single Seaters and Formula Juniors
NZ Sports Car Racing Series / Formula Libre (** on application, note below)
Pre 65 / Super Mini Challenge
Touring Car Masters New Zealand

It's not written, but the event has culled some classes from last year so that (amongst other things) it's all a bit less crammed and more focused on Classic Racing (and Historics too of course!).