Even the director of the Vietnam Fine Arts Museum here doesn’t know how many of the artworks and artifacts under his care are genuine and how many are extremely skillful copies. But he says he is going to try to find out.

There are nearly 20,000 of these mystery objects, on the walls and in storage, including paintings, sculpture, lacquerware, pottery, ancient statues and traditional crafts.

“We are making efforts to have a comprehensive review of items on display and in our warehouse,” said the director, Truong Quoc Binh. “After we evaluate the whole exhibit, we will try to label them all to show if they are original or not.”

Mr. Binh has been addressing questions about authenticity a lot lately. Curators and artists have been aware of the issue for years, but it became a matter of public discussion only in April, when it was raised at a conference on copyright in Danang.