KiwiRail engineers are this morning trying to clear a slip south of Kaikoura that partially derailed a freight train overnight.
The northbound train struck the slip between Claverley and Oaro in North Canterbury about 11pm. Two locomotives and six wagons of the 30-wagon train were derailed but were still upright.
The driver was not badly hurt and was treated at a local medical centre.
"It's a relatively inaccessible sort of spot, it's not easy to get machinery in and out of," KiwiRail spokesman Kevin Ramshaw said.
Details on the size of the slip were also sketchy.
It was most likely the line would be closed for much of today but engineers would have a better idea later this morning.
About six to 10 trains were due to use the line today and material bound for Christchurch could be moved by road if the slip could not be cleared quickly, Mr Ramshaw said.
The TranzCoastal Picton-Christchurch passenger service does not run during winter.
