The fire, burning about seven kilometres west of the city, is still not contained. The Coastal Fire Centre says it is not threatening any homes or structures, but is creating smoky conditions in Nanaimo itself.
Fire Centre spokeswoman Donna MacPherson says the fire is at the site of an active logging operation on private land and fighting it is more of a challenge because of branches and other slash lying on the ground.
"There is a lot of fuel on the ground so it's going to take our crews a while to work their way through this," she said.
"Right now the fire is fairly quiet because of the air tanker and skimmer work that was done yesterday [Saturday] afternoon, but we expect that as the water dries that we applied yesterday, the fire will put up a bit more smoke and be a bit more active."
A total of 21 firefighters, nearly double the number deployed to the fire Saturday, and two helicopters, are currently working the blaze.
The wildfire management branch says the fire is human caused. An investigation is underway to determine its specific cause.
Google Map: Mount Benson, Nanaimo, B.C.