Australia has notched its driest September on record, with less than a third of the usual rainfall for the month, extending the dry spell that has farmers and firefighters increasingly desperate for rain.

Victoria posted its second driest September, also collecting just a third of its typical September rain.

NSW also had another dry month, with less than half the normal rain, bringing the state's year-to-date tally lower than any year but 1902 and 1965, according to Blair Trewin, senior climatologist at the Bureau of Meteorology.

Last month was Australia's driest September on record. Credit:

"Below average rainfall covered almost the entire country" last month, Dr Trewin said, adding that it pipped 1957 as the driest September, and trailed only April 1902 as the driest for any month.