A blind busker who has been playing in Adelaide's James Place for 15 years claims he has become a target for an opportunistic thief.

Anthony Clarke takes up his usual position near Rundle Mall each day between noon and 2:00pm. His guide dog Steven is always by his side as he plays the banjo and mouth organ to passers-by.

Mr Clarke said a woman began taking gold coins from him four months ago.

"On one level I feel sad and sorry for her," he said.

"But what really annoys me is she actually targets me.

"For a while there she was gaining my confidence by buying me food and giving me drinks, waiting for me to put them in my bag, and then taking money out of my banjo case.

"She'd go through her lines of, 'I'm just putting money in', and all of these fantastic excuses she had."

Guide dog Utah Steven Wolfgang Clarke is always by his friend's side. ( 891 ABC Adelaide: Brett Williamson )

Mr Clarke said sometimes passers-by would call out to the woman and accuse her of taking his money.

He said the passers-by had been able to provide him with a description of what she looked like.

"She's a lady in her 50s, poorly dressed, blackish hair with a Mediterranean appearance," he said.

Mr Clarke said the woman had stolen from him twice in January and three days in a row in March.

The incidents have been reported to police.

Anthony Clarke has placed a steel mesh cover across his banjo case with the hope of foiling the thief. ( 891 ABC Adelaide: Brett Williamson )

Mr Clarke said when he was approached by people who gave him an uneasy feeling he would try to engage them in conversation.

He said he could recognise the alleged thief by voice.

Mr Clarke — a former gold medal and world judo champion — said the experience had shaken him.

"I know I can beat them, but why am I going to hurt someone over a few dollars?" he said.

"They could have a knife or some other weapon they could turn against me, so for me it is just not worth the risk.

"It's a fantastic experience busking," he added.

"I meet all sorts of people and I just have to remember she is only one instance in 15 years.

"I am not going to let her ruin my trust in good people."