Shortly before a heralded exhibition of Maya art opened in New York last week, scholars examining the artifacts at the American Museum of Natural History concluded that at least three pieces in the collection probably were modern fakes.

Those artifacts -- a figurine, a ceramic plate and a carved shell necklace -- were promptly removed, but a few other pieces on display are still drawing suspicious stares from some students of the ancient Maya civilization.

"In any exhibition, this kind of thing is likely to happen," said Charles Gallenkamp, who organized the collection on behalf of the Albuquerque Museum. "Our first thought was to leave them in to create some controversy. The question of faking is a very interesting one."

The idea of displaying the doubtful pieces with a label to that effect was strongly opposed by the Mexican family who lent the pieces, Gallenkamp said.

"It would be an embarrassment to have a real fake end up in the exhibition," said Peter Harrison of the University of New Mexico, a member of the committee of scholars who oversaw the exhibition. "Still, there's residual embarrassment that it got that far."

Such embarrassments are not uncommon in the world of Pre-Columbian art, where Maya objects can fetch pyramid-high prices. Determining what is real and what is not can be as difficult as deciphering the ancient hieroglyphs. The field has been raked by looters, sophisticated forgers abound, and if that is not enough to confound the experts, the Maya artisans themselves were highly unpredictable. All this has not dampened scholars' passions in arguing their cases for and against the authenticity of pieces.

It took a staff of experts six years to assemble the nearly 300 pieces from museums and private collections throughout Mexico, Guatemala and Belize, Gallenkamp said. New York is the first of six cities to display the collection, which is expected to draw 2 million people over the next two years. Washington is not among the six cities scheduled.

The exhibition, titled "Maya: Treasures of an Ancient Civilization," has been praised widely as the most extensive collection of Maya art ever assembled in North America.

In addition to the three pieces already removed, two stone panels and certain ceramic works have been the subjects of complaints by some museum patrons and scholars. One such piece, a ceramic cylinder found in fragments, was the subject of "somewhat overzealous restoration by Guatemalan officials," said Harrison.

Among those who expressed doubts about the removed pieces was Justin Kerr, a photographer and student of Maya ceramics. Kerr examined the ceramic plate and carved shell necklace in the museum's vault on April 16 and said he was immediately suspicious.

"It the plate was a fake," said Kerr. "It took no more than a minute to look at it and know it was wrong . . . There is a possibility this particular object was made not as a fake but as a souvenir. Airport art is what I'm talking about."

But the glossy catalogue for the exhibition, published months in advance in Italy, describes that artifact this way: "Delicate detailing and flowing calligraphic lines describe this unusual scene with a frame of glyphs." The ceramic "tripod plate" was said to be from "A.D. 500-800."

Kerr said the plate was no more than 20 years old.

His reasons: the glyphic message on the plate made no sense; the object was too hard to be of the Maya period, indicating it had been fired using modern techniques; the plate's three legs were from a different Mexican culture; the iconography was inconsistent with any Maya artifacts he had seen before.

Kerr's assessment did not surprise the museum's curator emeritus, Gordon Ekholm, who was the first to have misgivings about the plate, according to many involved in the exhibition. Another object, an ornate seashell carved as a necklace, also troubled Kerr. He said incisions in the piece indicated that it had been made using a jeweler's wheel not available to ancient Maya artisans.

The piece, dated between "A.D. 500-800" is featured prominently in the catalogue: "This pectoral (probably worn as a necklace against the chest) displays an important icon: a human head within the open jaws of a serpent."

A third piece, a figurine, had already been removed by organizers of the exhibition because of doubts about its authenticity.

The catalogue entries on the disputed pieces were written by Flora Clancy, one of five members of a committee overseeing the exhibition. An assistant professor of art history at the University of New Mexico, she said that when she wrote the catalogue entries she was working from photographs and had not yet seen the actual artifacts.

Those who have challenged the authenticity of a few of the pieces still on display say that even those serve a useful purpose.

Kornelia Kurbjuhn, who has a doctorate in ethnology and specializes in the Maya civilization, said she is convinced that one of the sculptured stone panels, depicting two captives held at spearpoint, is a modern hodgepodge of carvings copied from a number of well-known Maya works.

"It's very interesting this is in there for someone like me because I can take my students in there and ask them how they recognize this kind of thing. I don't think there's anything wrong with leaving it in there so long as peple don't stand in front of it and think it's an expression of Maya genius . . . We are heading for a time when they are going to make perfect fakes. I am dreading the day."