All the works were purchased in good faith

Gallery Director, Pierre Theberge

The National Gallery says it will examine works for suspicious gaps in ownership between 1933 and 1945.

The Art Gallery of Ontario has also said that about 20 works in its collection were also suspect.

Both galleries plan to post images of the art on web sites within the next few weeks in a bid to fill in the gaps.

On Tuesday, the United States Customs Service returned a 16th century Italian oil painting believed to have been stolen by US soldiers in Germany at the end of World War II to a gallery in Weimar.

And last month Washington's National Gallery of Art said it would return a 17th century Flemish oil painting to the heirs of a Jewish family, from whom the Nazis looted it sometime before 1941.

Plundered art

The World Jewish Congress says the Nazis plundered tens of thousands of artworks during World War II, most of which have not been returned to its rightful owners.

But the situation is made more complicated by the fact that, some of the art the Nazis stole was then seized by Soviet authorities at the end of the war.

This painting by Lucas Cranach the Elder was stolen from a Jewish collector

The highlight of the Canadian collection is a marble bust of Pope Urban VIII by 16th century Italian sculptor Gian Lorenzo Bernini, which is worth several million dollars.

Other works include "Bouquet of Flowers", a 17th century painting by Dutch artist Jan Breughel the elder, and "The Lean Kitchen", painted between 1652 and 1654 by Jan Steen.

"All the works were purchased in good faith," Gallery Director Pierre Theberge stressed.

Those wanting to lay claim to the works would need to provide some evidence of ownership, he said, be it documents or even family photographs that feature the work.