OTTAWA - It could be a messy start to the work week in southern Ontario and Quebec, with Environment Canada issuing freezing rain warnings for much of the region.

The national weather forecaster says a system known as a "Colorado low" will move across the lower Great Lakes on Monday.

It says, "A significant freezing rain event is likely, with several millimetres of accumulation."

The freezing rain will likely turn to rain Monday night in most areas, but areas including Montreal and Ottawa could continue to see freezing rain on Tuesday.

Forecasters are urging people to avoid non-essential travel, as highways and roads throughout the heavily populated region are likely to become slippery and hazardous.

The same system is responsible for a snowfall warning in northeastern Ontario, where forecasters predict up to 20 centimetres of snow by Monday night.