Residents alarmed by the large plumes of smoke rising out of bushland between Austinmer and Thirroul can rest assured it is a hazard reduction burn.
The burning is being co-ordinated by Fire and Rescue New South Wales for Wollongong City Council.
The area of land is public reserve behind Hill St and Foothills Rd, on land heading down the hill towards Seafoam Ave in Thirroul.
Some residents received a letter in their mailboxes on Wednesday afternoon warning them the burning was to start at 9am Thursday.
It was to be conducted in bush less than 20m from some properties and residents were warned to take precautions with their pets, washing on the line, and flammable material in their yard.
The letter was dated September 19 but arrived on October 9.
"To minimise the potential impact of smoke and embers from this fire, it is recommended that you consider ... protecting or removing items that may be affected by hot embers, smoke or radiant heat (eg outdoor furniture, pool covers, plastic items, pets etc)," it said.
One resident, who did not receive the letter and found out when a friend saw the plumes of smoke, said this was a large list of things to prepare overnight given the short notice.