A vast cloud of ash spewing from a Chilean volcano has forced dozens of flights to be cancelled across South America, while mud and rain mixed with ash poured down on the resort areas in the region.

Three days after Chile's Puyehue volcano began spewing debris, all flights in and out of the two busy Buenos Aires airports were scrapped on ?Tuesday after meteorologists said a portion of the cloud had moved as far as the Argentina capital, even though at 5,000m high it was not visible to residents.

More than 90 per cent of the flights in an out of Uruguay were also cancelled, airport officials said.

Al Jazeera's Craig Mauro reports from Buenos Aires.