Tough times for a big irrigation project in Victoria, after the lead contractor walked off the job.

The $40 million Harcourt Rural Modernisation Project has been suspended for a second time, with contractor Redline throwing in the towel again, this time over a disagreement on the pipeline's design.

Work had only just re-started after design errors and changes were rectified in February.

But Redline says it had a limited amount of work to do while it waited for formal revised design drawings and instructions from Coliban Water.

Coliban Water says Redline has what it needs, and there are no valid grounds on which to suspend the Harcourt works.

Redline has thanked the community for its patience while the stoush continues, and Coliban is reportedly working on a response to Redline's actions.

The plans for the project include two pumping stations and 65 kilometres of pipeline.