The company has the contract to complete a more than $4 million water services upgrade in Elizabeth St, St Andrews St and the western end of Joseph St for the Gore District Council.
The project, which includes replacing the entire Elizabeth St water main, wastewater pipeline and installing a new stormwater pipeline under the road, started in January.
Three Water assets manager Matt Bayliss said the excavator was digging a trench about 5m deep when the walls of the trench gave way and it tipped in.
"Fortunately no-one was hurt.
"We made the decision to stop work and review the work methodology to make sure it could be completed safely."
The incident was reported to WorkSafe.
"Fulton Hogan have provided them with information and WorkSafe are happy for the work to continue now."
Rain and soggy ground conditions were contributing factors to the trench giving way, Mr Bayliss said.
The collapse happened about half way up the street where a deeper trench for pipes had to be dug because of the rising height of the land.
The work on this section of the street was taking longer than anticipated because the trench needed to be 5m deep, he said.
Originally it was expected the work would be finished in October but this was unlikely, especially with the week’s delay, he said.
He hoped the work would restart as soon as possible.
