As at 3.30pm the fire had jumped two roads, Bungendore Road and Mount Fairy Road, and was continuing to burn east.

More than 30 units from the Southern Tablelands and Lake George zones, as well as ACT's Fire and Rescue and Royal Fire Service, with several strike forces from the outside the region expected to join the fight.

The NSW Fire and Rescue today announced the first total fire ban for the year, with severe weather warnings expected to impact this blaze.

The ACT's Rural Fire Service liaison officer Greg Potts said they may incorporate aerial tankers.

Residents have not been told to evacuate but the RFS is instructing people to act according to their fire survivor plan, which may include evacuating particularly for those with young children.

"It's a fast running fire and certainly any fire that is likely to or threaten property is scary for the residents and owners," Mr Potts said.

"Plus, we are looking at slightly higher fire danger rating for tomorrow (Wednesday) so there will be a lot of continuing work on containing this fire once we have got it under control."

For updates on the fires go to www.rfs.nsw.gov.au or monitor local media.

ACT and NSW firefighters from the Rural Fire Service and Fire and Rescue units are tackling the blazes.

Firefighters from the Southern Tablelands had also been diverted to help tackle the blaze near Tarago.

More to come.