Op shoppers aren't just nabbing a bargain when they pop into charity stores, they are also helping their communities, says Anglicare's operations manager of shops and factories Julie McAuley.

National Op Shop Week begins on Sunday and Ms McAuley said buying from op shops meant charities had more resources to help disadvantaged people.

"We want to make people aware of what their op shops do for the community," she said.

"If they go to a charity op shop, they are putting money back into their communities to help the less fortunate."

The week is a joint initiative between not-for-profit organisation Do Something! and the National Association of Charitable Recycling Organisations to help charities raise more money by increasing their clothing donations and boosting sales.

Many charities are taking part, including Salvos Stores, Lifeline shops and Anglicare outlets.

Ms McAuley said people were taking an interest in op shops.

"While a lot of the mainstream retailers sell things cheaply, when you can get still stuff for the same price in op shops, [but it's] better quality because if it's lasted long enough to go through an op shop, you know it's good quality."

National Op Shop Week runs from August 24 to 31.

Donated clothing should be clean, undamaged and as wrinkle-free as possible. Keep items that come in pairs such as shoes and socks together and check garment pockets.