Mudslides in western Colombia after days of heavy rain killed at least 36 people at the weekend and dozens are still missing, according to an updated official toll.

In one tragedy in Manizales, the capital of Caldas, a landslide swept into homes, leaving 29 dead and many missing; then in Cali on Sunday, a rain-swollen river burst its banks and killed seven people, most of them children.

The national emergency management office said it was not yet clear how many people were still missing in the two incidents.

About 150 rescuers in addition to 450 police were working into the night late Sunday trying to find survivors among the rubble in Manizales, a city of about 350,000.

Colombia has been battered by one of its worst rainy seasons in living memory this year, with dozens killed and some 250,000 people having to be evacuated from their homes.

Between April 2010 and April 2011, particularly heavy rains triggered by the La Nina phenomenon -- associated with cooler-than-normal water temperatures -- left over 400 people dead and 3.6 million affected by the disaster.