The Manitoba government says it will begin increasing the outflow from the Shellmouth Reservoir to make room for the anticipated spring run-off from the upper Assiniboine River.

The increased outflow will affect river levels all the way to Winnipeg in the coming weeks.

MLA for Riding Mountain Greg Nesbitt says the increase will begin on Monday.

"The current outflow is 50 cubic feet per second (cfs)," Nesbitt says. "The outflow will be increased to 450 cfs."

Nesbitt says the government expects the increase to result in the river rising by up to half a metre from Russell to Brandon.

In Winnipeg, the river is forecast to rise by anywhere up to 1/3 of a metre in about two weeks.