Hundreds of fire-affected residents in Wollondilly and the Southern Highlands have visited evacuation centres in the past few days.
Mittagong RSL general manager Craig Madsen said the club had provided shelter for between 200 to 300 people and their pets.
Representatives from the government, the Red Cross and the Salvation Army are on hand to help provide support.
Mr Madsen said his team had been "extremely busy" with the increased demand on its hospitality services.
"Everyone's working extremely hard," he said.
"It's reaching a stage where we'll have to refer people to Moss Vale Services Club."
However Mr Madsen said his team would do its best to accommodate as many people as possible.
"We're going to play it by ear. If people aren't placed tonight, we'll have staff members staying back [to accommodate them]," he said.
Moss Vale Services Club supervisor Stacey Cuttriss said the club had accommodated a small number of fire-affected residents on Saturday.
"We've two or three people come in. They've come from Canyonleigh because of the smoke," she said.
She said people who needed to evacuate could come to the club at any time day or night.
Mr Madsen said he had several staff rostered off to fight the Green Wattle Creek fire.
"Like everyone else, we're concerned about their safety," he said.
"They do a fantastic job. They're awesome at their jobs and they're awesome volunteers.
"I'd like to wish all of the Rural Fire Service staff all the best."