A recently re-opened rail link between Blenheim and Christchurch has been temporarily closed by slips near Kaikoura.
KiwiRail said recent heavy rain has led to the closure of the Main North Line while repairs are done.
The acting chief executive, David Gordon, said rainfall caused 31 slips, including three major slips that came down on to the track and road.
He said the Main North Line recently began operating a limited service at night, while the rebuild continues during the day.
Mr Gordon said services were expected to begin again at the end of this month.