An overworked NSW Rural Fire Service boss says this week's forecast rain is the best news firefighters have had for many months.
Rain is expected across much of the state from Tuesday including fire grounds in the Snowy Mountains, southwest of Sydney and South Coast regions.
"From a fire point of view, this is the best week we've seen for many, many months in terms of easing some of the conditions," RFS commissioner Shane Fitzsimmons told the Nine Network on Tuesday.
"We are expecting right across the state - particularly the Great Dividing Range which happens to coincide where all this fire activity has been for the past few months - widespread 30 to 80 millimetres."
Some areas with thunderstorms could receive up to 100mm, Mr Fitzsimmons added.
"If it's falling on fire grounds that will certainly have a positive effect right across the fire fighting effort."
The downside is there could be localised flash-flooding, significant erosion and problematic run-off into water catchments.
The RFS commissioner said to protect drinking supplies "filtration and other equipment is being deployed into the water systems".
The fire service is working closely with the SES, NSW Police and the Bureau of Meteorology to track where the heaviest falls were likely to be.
So far this bushfire season some 2176 homes have been destroyed across NSW. Of that number, 1260 have been lost in the past fortnight.
"This figure is likely to increase as (assessment) teams continue to work through fire-affected areas," the RFS tweeted on Tuesday.
There are still more than 100 fires burning across NSW.
The BOM says it's difficult to predict exactly how much rain will fall this week because the downpours will be inconsistent.
Bega on the South Coast is expected to receive between 3mm and 10mm on Thursday when most rain is predicted to fall.
However, in Cooma, just 100 kilometres inland, greater falls of between 8mm and 25mm are forecast.
