Kinder Morgan Canada has asked the National Energy Board to waive an approval condition of the Trans Mountain pipeline expansion because it might delay completion of the project.

Shawn Denstedt, a lawyer at Osler, Hoskin & Harcourt representing Kinder Morgan Canada subsidiary Trans Mountain, said in a letter to the NEB that it needs to be allowed to install mats to deter fish spawning as soon as possible to have them in place before spawning season.

The NEB told the company last week that it had to stop installing the deterrent mats because they're considered construction activity, and the company does not yet have all conditions approved for pipeline construction.

Denstedt said if the NEB doesn't grant Trans Mountain's request "expeditiously," then installations of the mats and corresponding crossing construction could be delayed by a year, potentially impacting when the project is complete.

The NEB said Thursday that it's continuing with its assessment, but that Trans Mountain has halted plans to install five more deterrent mats after having already installed eight.

The controversial $7.4-billion Trans Mountain expansion project, which would nearly triple the capacity of the pipeline system running from Alberta to B.C.'s southern coast, is facing significant scrutiny from the many environmentalists, Indigenous groups, and B.C. governments that oppose it.