The trial piling work for the second Ashburton bridge has been completed, marking a key early step in the long-planned construction project.

NZTA Waka Kotahi confirmed the work took longer than expected due to weather delays, the late arrival of a crane, and additional testing carried out to refine the bridge design.

Most piling equipment will be removed this week, and fencing will be rolled back to restore two-lane access through the site.

Part of the gravel area will remain fenced off to store piling gear for use next year.

The project team is now preparing for a compaction trial, which will test whether gravel sourced from the northern part of the river can be compacted sufficiently to form a stable foundation.

A suitable site away from residential areas is still being identified.

Survey work and potholing are also continuing along the bridge alignment as crews locate underground services such as power, telecommunications and water lines to support the detailed design phase.

Further updates on the pile testing and compaction trial are expected in December.