CHICAGO (Reuters) - A panel of scientists is disputing a World Health Organization report published earlier this year that concluded glyphosate, the world's most widely used weed killer and main ingredient in Monsanto Co's Roundup herbicide, is probably carcinogenic to humans.

The 16-member panel, assembled by Intertek Scientific & Regulatory Consultancy, will present its findings to the annual meeting of the Society for Risk Analysis on Monday, aiming to publish the study at a later date after peer review. Monsanto paid Intertek for the panel's work.

The group said that the WHO's International Agency for Research on Cancer (IARC) misinterpreted or incorrectly weighted some of the data it reviewed and ignored other data before classifying glyphosate as a probable human carcinogen, according to an abstract of its findings.

"Thus, none of the results from a very large database, using different methodologies, provides evidence of, or a potential mechanism for, human carcinogenesis," the abstract said.

The panel's assessment is similar to that of the European Food Safety Authority (EFSA), which last month said glyphosate was not likely carcinogenic.

IARC was not immediately available for comment.

The U.S. government says the herbicide is considered safe. In 2013, Monsanto requested and received approval from the U.S. Environmental Protection Agency for increased tolerance levels for glyphosate, which is mainly used to kill weeds in fields planted with corn and soybeans that are genetically modified to survive it.

But concerns about glyphosate on food have been a hot topic of debate in the United States recently and contributed to the passage in Vermont last year of the country's first mandatory labeling law for foods that are genetically modified.

Critics say that industry-linked scientists are downplaying the risk to human health and trying to discredit the IARC report by casting doubt on some of the scientific studies that it reviewed.

Ten of the 16 scientists on the Intertek panel have been consultants for Monsanto in the past and two others are former Monsanto employees, according to a roster published on Monsanto's website.

"IARC's goal was just to score the cancer hazard, that's it. They've looked at all the data and they have really convincing evidence," said Jennifer Sass, senior scientist with the National Resources Defense Council.

"What this panel is trying to do is death by a thousand cuts. They're taking a good stack of evidence and starting to hack through it to try to kill it," she said.

(Editing by Cynthia Osterman)