A West Coast rail tunnel has partially collapsed affecting freight services.

KiwiRail Chief Infrastructure Officer André Lovatt told Chris Lynch Media around 2.15pm on Saturday, a digger operator noticed some crumbling while carrying out planned maintenance on the Tawhai tunnel south of Reefton.

The operator exited the tunnel safely before a partial collapse occurred.

“The 370m long tunnel remains close” Lovatt said.

“A safe entry plan needs to be developed and approved to enable us to fully assess the situation, and determine the scope of work required and the timeframe for reopening.

“No passenger services use this line, and we are talking to affected freight customers.: