THE HAGUE—Works of art looted from Dutch Jewish victims of the Nazi regime may be returned to the rightful owners' heirs thanks to a new probe announced Tuesday by the national association of museums.

"We have information about auctions that took place just before and during World War II at which it is known that Jewish people were forced to sell items," association director Siebe Weide told Agence France-Presse.

Other pieces were stolen, and yet more were seized after being left behind by fleeing Jews.

The new investigation into the collections of some 100 museums, concerning items acquired from 1933 onward, will run for four years.

"It is the ethical thing to do," said Weide. "After the war, these matters were not taken up with enough consideration for the Jewish people. And that generation is ageing -- we have to do it now."

He said the investigation, sponsored by the Dutch state to the tune of Є1.3 million ($1.7 million), would seek to confirm the provenance of each and every museum item, most of them now owned by Dutch municipalities.

A list will be published of works of art from dubious origin, leaving the option for the original owners or their families to put in claims. These would be adjudicated by a special restitution committee.

The Dutch organization "Origins Unknown" says thousands of art objects were sold, stolen or confiscated during the war and ended up in Germany.

In the 1950s, the Dutch government retrieved some of the works and restored some to their rightful owners, but many remained the property of the state and were exhibited in a variety of museums.

Weide said much research was done over the past decade, but nobody knew exactly what the probe would yield.

"It is a bit like searching for a needle in a haystack. It would surprise me if there were more than 100 pieces."