At 7.11pm it was reported on the Fires Near Me App, and in comments, that the fire was being controlled and contained.
The Hume Highway is closed in both directions near Yass due to grass fires.
Motorists in both directions can use the Yass Valley Way and the Barton Highway instead.
Motorists should allow extra travel time as traffic is heavy.
At 7.08pm, RFS operations officer Michael Gapps said there were multiple fires in the area but fire crews were gaining the upper hand on them.
"We have 30 trucks down there combating the blaze," Mr Gapps said.
"We believe the fires were caused by a truck that had a mechanical issue."
Other roads closed due to bushfires around the South West and South Coast:
On the South Coast:
- * Braidwood to Nelligen: the Kings Highway is closed
- * Braidwood to Moruya: Araluen Road is closed
- * Nowra Hill to Charleyong: Nerriga Road/Braidwood Road is closed
- * Jerrawangala to Tomerong: Turpentine Road is closed
South West of Sydney:
- * Hill Top to Couridjah: Wilson Drive/West Parade is closed
- * High Range to Taralga: Wombeyan Caves Road is closed