The Calbuco volcano in southern Chile has erupted again, releasing a large column of smoke just over a week after it spectacularly roared to life following half a century of inactivity.

"As predicted, the third eruptive pulse at the Calbuco volcano has arrived. Red alert," the National Geology and Mines Service wrote on its official Twitter account on Thursday.

A towering plume of grey smoke and ash rose from the crater, prompting authorities to once again evacuate a 20km radius around the volcano, where workers and residents had been granted limited access to begin the clean-up effort.

The volcano surprised residents of the Los Lagos region with two eruptions last Wednesday and Thursday after 54 years of inactivity, belching a 15km column of ash into the air before spewing bright orange and red lava.

Authorities evacuated more than 6000 people out of the area and declared a state of emergency after the eruptions, which spewed some 210 million cubic metres of ash that blanketed the region and disrupted flights across a broad swath of South America.