Fire and Rescue NSW (FRNSW) crews extinguished a semi-trailer fire that blocked part of the Hume Highway north of Gunning on Thursday last week.

Both trailers of the B-double caught fire just around 1am but the driver managed to separate the prime mover just in time.

The truck was carrying a mixed load that included aerosol cans which exploded from the extreme heat.

Fire crews from Yass Fire Station assisted the Rural Fire Service for two and half hours as they extinguished the blaze.

Both trailers were destroyed by the fire and one southbound lane was closed during the incident. Both lanes are now open.

The cause of the fire is not yet known.

Acting Superintendent Mathew Sigmund from Fire and Rescue NSW (FRNSW) said this is a timely reminder that calling Triple Zero (000) for a fire emergency can be the difference between life and death, or a building or other property being saved or destroyed.