Weather patterns delivering an exceptionally dry winter across south-eastern Australia show little sign of breaking up, heightening concerns the coming fire season will be an early and active one.

Fire authorities won't formally release predictions for spring and summer until September. Wet periods in autumn, though, curbed hazard-reduction burning to half the year-earlier totals in NSW and curtailed it in Victoria.

Flammagenitus forms from bushfire smoke. The type of cloud was formerly known as a pyro-cumulus. Credit:Alex Ellinghausen

"The next four to six weeks are going to be very important," said Ben Shepherd, an inspector and head of media at the NSW Rural Fire Service.

"Many of the agencies are looking for that opportunity to get out there and start those [hazard-reduction] burns again in earnest" before conditions turn too windy and warm, he said.