At least 683 residential properties in NSW have been confirmed destroyed by the bushfires still ravaging the state, with experts warning today that conditions will sharply deteriorate over the next few days.

More than half of the 90 bushfires burning in the state remain uncontained, NSW Rural Fire Service (RFS) Commissioner Shane Fitzsimmons said this morning.

A live map update on the RFS site shows six fires north of the Blue Mountains National Park are at the maximum emergency warning alert level, meaning lives could be in danger if residents delay in leaving the affected area.

“Unfortunately we are now in summer [and] we know that we can expect hotter conditions as the weeks and months roll ahead,” Mr Fitzsimmons said.

“Between now and February we can expect below-average rainfall and above-average temperatures."

He says this points to “increased fire dangers [and] increased fire activity.”

The prolonged drought has also made conditions more difficult.

Mr Fitzsimmons says less than 1% of NSW is drought-free. “The dryness in the fuels makes it extremely flammable and we know we have still got months of challenges ahead.

“The only forecast for rain is expected at this stage to be late January, early February.”

Insurance claims from the NSW and Queensland bushfire catastrophe have increased to 2000 since the last update on November 22, when insurers reported they had received 1525 claims.

An Insurance Council of Australia spokesman says insured losses up to today have been estimated at about $165 million. At this stage the official figure is little changed from the November 22 estimate.

Insurers are awaiting more accurate information on the number and estimated cost of losses, which is not unusual in bushfire situations where access to affected areas is often delayed.