A collapsed roadway at a FortisBC worksite has forced crews to close part of a major traffic artery through Coquitlam, leaving drivers and the city's mayor frustrated.

The utility said workers noticed "ground movement" near Como Lake Avenue and Banting Street on Tuesday, and decided to block all westbound traffic as a precaution.

“They immediately secured the area for safety purposes so they could inspect the trench,” FortisBC spokesperson Grace Pickell told CTV News Vancouver.

Pickell said it turned out a five-metre section of roadway had dropped around 20 centimetres, but said it wasn’t a safety issue and wasn’t technically a sinkhole.

Coquitlam Mayor Richard Stewart posted about the road closure on Facebook Thursday morning, dredging up the ongoing conflict between the city and the utility giant.

“That road belongs to the taxpayers of Coquitlam,” Stewart said. “It doesn’t belong to Fortis. And Fortis is treating it as if it’s their own.”

The City of Coquitlam denied FortisBC a permit to replace the aging gas line under Como Lake, part of a major infrastructure permit that stretches from Vancouver, but the BC Utilities Commission decided in the utility’s favour and the project went ahead.

One of the city’s chief concerns is that FortisBC will leave the existing line in the ground rather than removing it, which the utility in the past has called a less disruptive option.

Stewart said the latest setback has built upon what were already "enormous challenges for residents," in part because there are three schools along the closed corridor.

Pickell told CTV News it would likely be a week before the westbound lane could be reopened, and work on the section of project resumed. It’s not clear what the delay will mean for the overall project timeline.

The 30-inch gas line was installed in the 1950s, and is reaching the end of its lifespan.

The utility said the line services more than 210,000 homes and businesses, including more than 30,000 in Coquitlam.

With files from CTV Vancouver's David Molko