Fears more wild weather could disrupt work to repair a major South Island rail bridge

One of the 34 piers on the 610-metre long Rangitata bridge was washed away due to high flood waters on Friday.

All train movements between Ashburton and Timaru have been paused since then.

Kiwirail chief infrastructure officer Andre Lovatt says work has started to repair the bridge today - and by next week they aim to begin building temporary supports.

He says the work will take up to two weeks, and allow freight trains to resume running - but further rain at the end of next week could disrupt the work.

A permanent replacement of the pier will be carried out once the bridge is operational.