A grass fire burnt out two hectares of property between Yass and Gunning on Wednesday.
Five tankers and 12 firefighters were sent to extinguish the fire.
A spokeswoman said high winds in the area hampered efforts, but the fire was contained by 9.30am.
The NSW Rural Fire Service was alerted to the blaze, near the intersection of the Hume Highway and Lade Vale Road, at 8.10.
Earlier in the morning all southbound lanes of the highway were closed, but were opened a little later.
At 12.30pm the bulk of the fire was out, and firefighters remained on site, conducting mopping-up operations.
No homes were threatened by the fire.