SYDNEY, Australia — More than 85 fires burned across Australia’s east coast on Tuesday, 40 of them out of control, as officials warned that catastrophic conditions would worsen through the afternoon and evening, with intensifying winds blowing flames toward larger cities and towns.

More than 100,000 homes are at risk over the coming days as a combination of drought, heat and blustery winds bears down on New South Wales, the country’s most populated state.

“The conditions are expected to get worse,” Shane Fitzsimmons, the Rural Fire Service commissioner, said on Tuesday afternoon in Sydney. “There’s still a way to go before they reach the potential of the forecast.”

“Complacency kills,” he added. “We cannot afford to be complacent.”

The fires, which began burning in earnest over the weekend, have caused four deaths and destroyed more than 150 properties, with a handful more added every few hours.