It's Wear Orange Wednesday - an annual initiative which encourages people to don the SES colour to show gratitude to the men and women who give up their time for the service.

"Because we're volunteers, thank yous are how we get paid," Maitland SES community engagement officer Alex Varley said. "A lot of time the community wants to thank us but they don't know how, so this is their chance."

The day is part of National Volunteers Week, which runs May 20-25.

Maitland SES has about 70 volunteers, who are on hand 24-hours a day, 7 days a week, ready to respond to calls for assistance - whether that be flood rescues, car accidents, land search and rescue or otherwise.

Ms Varley joined the service as a teenager, after growing up with parents in the emergency services industry.

"It was a natural move for me," she said. "But because I was in year 10, people thought it was such a weird thing for me to do.

"They were playing sport, I was cutting down trees."

Fellow member Sarah Thomson joined as a way to give back to her community and learn new skills after being a stay at home mum for eight years.

NSW SES Commissioner Kyle Stewart said wearing orange was a chance to acknowledge all the people who put on the orange overalls to help in difficult times.

"It's also a time to acknowledge those who support our volunteers - their families, friends and employers - to help communities in need," he said.

Maitland MP Jenny Aitchison said the small token would show appreciation for the sacrifices SES volunteers make to help the community in times of need.

Members of the community are invited to attend a selfie station in Maitland Park today between 12.40 and 1.40pm.

People are also encouraged to post a selfie to social media in their orange gear and tag it #thankyouses and #WOWDay.