The ban extends from the U.S. border in the south to Bissett and Hollow Water in the north, and from the Ontario border to the eastern shore of Lake Winnipeg, La Broquerie and Richer.
It also includes the Whiteshell provincial parks, the North-West Angle Provincial Forest and Sandilands Provincial Forest.
“It's very dry, and it has been dry for a while. They got a lot of rain through there in the spring, but unfortunately, July was a very dry month,” said Gary Friesen, manager of the fire program with Manitoba Conservation.
“We're at the point now where it doesn't look like there's going to be much rain in sight for the next week or so, so we're just trying to prevent any unnecessary fires.”
Precipitation in southeastern Manitoba, including Winnipeg and the border region, was less than 40 per cent of normal in July, according to Agriculture Canada.
Winnipeg received just 10 millimetres of rain in July.
About 12 wildfires are burning in the region, many of them sparked by lightning strikes.
Crews are making good progress on those fires, Friesen said, but conservation authorities are hoping to prevent the additional burden of human-caused fires.
The ban applies to all open fires, including campfires, and all existing burning permits have been revoked.
On the other side of the Manitoba border, dry conditions and periodic thunderstorms have contributed to one of northwestern Ontario's most active fire seasons in recent memory.