Two fire engines were seen on the southbound carriageway at junction 29 for Bamber Bridge at 10am by Post reporter Tom Earnshaw, where firefighters were attending to a silver car which had set on fire.
Lancashire Police were also seen holding traffic while the fire was dealt with.
A spokesman for Highways England said: "There was a car fire and traffic officers closed one lane so the fire service could come and put out the fire.
"Traffic was held until the fire was put out and when put out it was put in the hard shoulder.
Crofters Hotel and wedding venue in Garstang shuts down to make way for 66-bed care home
Ice cream sales 'double' at Lancashire-based firm as heatwave hits UK
Evans Cycles: national bike firm opens second Preston store to power cycling boom in city
Lancaster nightclub to reopen two months after 22-year-old’s death
Iconic Preston cafe to escape refurb of building it sits in
"Traffic was released fairly quickly."
An AA spokesman said that traffic had been released, with one lane now closed and slow traffic "due to vehicle fire on M6 southbound at junction 29".
They added that lane one of three is closed.
More to follow