A PRESTIGIOUS art gallery has broken off its representation of a popular Sydney photo artist and cancelled his exhibition - which was due to open this week - after revelations he used photos taken by others without acknowledgement to make his work.

Tim Olsen Gallery says it plans to refund at least half a dozen buyers of images by Ben Ali Ong after the case came to light in the Herald on Saturday.

Ethical debate ... Tim Olsen. Credit:Lee Besford

''It would be hypocritical to take the money in the circumstances,'' the gallery owner, Tim Olsen, said yesterday.

Ong, 30, was among the first photo artists the Woollahra gallery took into its stable, fuelling the growing profile of an artist whose work had gained acclaim and made the finals of leading prizes.