Manitoba's unusually warm fall weather is causing problems for firefighting crews in some southern areas of the province.

Several grass and brush fires are burning near Portage la Prairie, about 70 kilometres west of Winnipeg.

That has prompted the Office of the Fire Commissioner to urge people to be cautious, particularly farmers burning stubble off their fields.

"We're asking them … to hold off on any burning that they were planning and to respect the burn bans that are in place by their local municipalities," said Dave Schafer, OFC manager of operations for the western part of the province.

A fire has been burning in the Delta Marsh area — an extensive open marsh located near the south shore of Lake Manitoba, about 24 kilometres north of Portage la Prairie — since Tuesday night and crews are still trying to get it under control.

Provincial stubble burning regulations are only in effect until Nov. 15 but individual municipalities have the power to institute bans later than that, Schafer said.

Temperatures in the Portage la Prairie area hit 15 C on Tuesday and were forecast to reach 13 C on Wednesday.

The normal temperature for this time of year is a daytime high of -3 C and a low of -11 C.

The long-term forecast doesn't call for daytime temperatures below freezing until next Tuesday, with a predicted high of -1 C.