Woolworths has apologised to a Sydney woman who says she was treated like a thief by a security guard because she was wearing a burns compression mask.

Sarah Manganas, 25, has third degree burns to her face, neck, chest and upper body, and needs to wear a medical burns compression suit and face mask, after an ethanol heater exploded in her face.

"I think it's been a good experience because it's challenged me to be the best person I can sort of be," she said.

However, her fighting spirit was challenged by a security guard during a shopping trip to Woolworths at Sydney's Town Hall yesterday.

Mrs Manganas said she was treated like a criminal due to her mask.

A security guard followed her around the shop before confronting her, she said.

"He was shouting out, 'Hey, you, why are you wearing that? What are you doing?'," she said.

"At first, I didn't think it was me, so I ignored it and then he shouted it out again, 'Hey, you!'," she said.

Mrs Manganas was forced to explain herself in front of other shoppers, before leaving in tears.

Her husband Andrew said he was appalled by the actions of the professional guard.

"They need to make sure everyone is trained to recognise medical masks and religious garments and all that sort of stuff, so that they're not making a mistake and embarrassing people unnecessarily," he said.

Woolworths apologised to Mrs Manganas today, and called the guard's behaviour unacceptable.

All security staff will be given refresher training in customer service, the company said.

Mrs Manganas said she did not want any other burns victims to be treated like she was.

"I don't want this to happen to anyone else who has been burnt, because I know from experience that they're already going through enough," she said.