The Auckland metro rail network shuts for commuter trains from December 26, 2022 to January 15, 2023 and the Wellington network closes from December 26 to January 3.
Bus replacement services will run during these times.
About 1100 staff and contractors will be working on tracks across Auckland, with another 250 deployed in Wellington.
“The extended rail corridor access, without commuter trains running, allows us to get a huge amount of work done over a short period of time.”
Gordon said maintenance vehicles and freight trains would still be using tracks so people should still be careful around rail lines.
Among the major projects in Auckland are the Wiri to Quay Park/Third Main, Papakura – Pukekohe electrification, and Southern Stations upgrades, along with track works near Ports of Auckland, off Tamaki Drive and in other areas to support the City Rail Link (CRL).
Teams in Auckland will also do general maintenance, such as replacing worn rail and sleepers and maintenance machines such as tampers, ballast cleaners and rail grinders will operate across the network - and through the night in some places.
In Wellington, new signalling gear will be installed on the Kāpiti Line between Porirua and Plimmerton, along with visual monitoring equipment north of Plimmerton on the Kāpiti Line, which will allow speed restrictions to be lifted in some slip-prone areas.
The Johnsonville Line and the Kāpiti Line north of Paekakariki will remain open.