WASHINGTON -- The row over a decision by US space agency NASA to ban Chinese researchers from a forthcoming conference on exoplanet research should be served as a wake-up call for some US legislators, a US expert said Monday.

The rejection based on a controversial law, initially crafted in 2011 by Frank Wolf, chairman of the House Appropriations subcommittee that funds NASA, sparked a boycott from several prominent American scientists, including Professor Debra Fischer of Yale University, and Professor Geoff Marcy of the University of California, Berkeley.

Last week, NASA administrator Charles Bolden vowed to reconsider the applications of six Chinese researchers to enter the Second Kepler Science Conference on exoplanets at California's Ames Research Center scheduled for November 4-8, but organizers of the meeting said there would be little chance for the Chinese researchers to pass security clearances in time due to the ongoing government shutdown.

"Congressman Wolf may finally be waking up to the unintended negative consequences of his actions," Gregory Kulacki, a senior analyst with the US-based Union of Concerned Scientists' Global Security Program, said in an interview with Xinhua.

"But until the legislation he insisted on injecting into US disputes over the federal budget is removed, these kinds of incidents will remain a constant feature of US-China relations in space," he said.

NASA officials have said the restriction was based on a law passed in 2011 and signed by President Barack Obama that prohibits government funds from being used to host Chinese nationals at NASA facilities.

Kulacki said the language of the law prohibiting NASA from engaging Chinese researchers is "so broad, and the legal and financial penalties associated with potential violations so threatening, that even US organizations not directly administered by NASA are afraid to reach out to colleagues in China."

Wolf himself has sought to correct an article on the matter, as well as NASA's stance, according to a letter issued by Wolf's office to Bolden on Tuesday.

"Unfortunately, the article is riddled with inaccuracies, as is, it appears, the guidance provided by NASA Ames staff to the attendees," said the letter.

Wolf claimed in the letter that the law "primarily restricts bilateral, not multilateral, meetings and activities" with the Chinese government or Chinese-owned companies. He also said it " places no restrictions on activities involving individual Chinese nationals unless those nationals are acting as official representatives of the Chinese government."

Kulacki, however, believed that Wolf is to blame for "this embarrassing and unfortunate incident."

He said that Wolf made it "fairly clear" in the letter that his objections to cooperation "have little to do with" concerns about technology transfer, but are largely motivated by political concerns.

"Hopefully this incident will make it clear to him that the law he enacted" caused negative consequences, Kulacki said.

Despite the fact the distrustful atmosphere persists, the expert said he remained hopeful that US-China cooperation in space science and exploration is possible.

"There are only a few individuals within the United States Congress, in particular Congressman Frank Wolf, who are standing in the way of that happening," Kulacki said.

"Chinese scholars should understand that their colleagues at NASA are anxious to work with them on a variety of space science projects," he added.