NASA has taken a step backward and exhibited a "Cold War mentality" by barring Chinese scientists from an upcoming space science conference, and the US space agency's refusal to exchange space technologies with China is a loss to the United States, Chinese analysts said on Wednesday.

NASA recently announced Chinese nationals would not be permitted to enter the venue of the Second Kepler Science Conference at California's Ames Research Center from Nov 4 to 8 - a decision based on a law passed in 2011 to prevent NASA funds from being used to cooperate with China or to host Chinese visitors at US space agency facilities.

"NASA's discriminatory practice has led to many US and European scientists boycotting the conference. The conference itself should not be politicized," Chinese Foreign Ministry spokeswoman Hua Chunying said on Wednesday.

US congressman Frank Wolf, who drafted the law on which the restriction is based, said on Tuesday a report on the controversial action was inaccurate, AFP reported. Wolf chairs the House Subcommittee on Commerce, Justice, Science and Related Agencies.

The law bans NASA funds from being used to work "bilaterally in any way with China or any Chinese-owned company" or being "used to effectuate the hosting of official Chinese visitors at facilities belonging to or utilized by NASA," according to a copy of the legal text sent to AFP by Wolf's office.

Wolf's office issued a letter to NASA Administrator Charles Bolden on Tuesday, seeking to correct an article on the matter that first appeared on Friday in The Guardian newspaper, as well as NASA's stance.

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

The law "primarily restricts bilateral, not multilateral, meetings and activities with the Chinese government or Chinese-owned companies," it said.

"It places no restrictions on activities involving individual Chinese nationals unless those nationals are acting as official representatives of the Chinese government."

Gong Li, director of the Institute of International Strategic Studies of the Party School of the Communist Party of China Central Committee, said the focus of the conference is far from the Earth, and relating US national security concerns with the conference is a "Cold War mentality".

"The US took similar actions against the former Soviet Union during the time of the Cold War. I regret to see the US backtrack to such a mentality in international technological exchanges today," Gong said.

The ban also showed Washington is worried about China's fast development, especially in space technology, Gong said.

"The bill shows that there are many American politicians such as Wolf who are profoundly nervous about China's development," he said, adding that Wolf's letter to NASA is unlikely to change the situation.

"Space technology cooperation benefits both countries, especially when China is no longer an underdeveloped player in this sector. Refusal of an exchange with Chinese scientists is indeed a loss for the US. I hope they can change this mindset," he said.

Su Hao, a professor in Asia-Pacific studies at China Foreign Affairs University, said NASA's decision contradicts the general trend of China-US relations.

"Washington always emphasizes Sino-US relations as a strategic partnership, while more senior US government officials are gradually accepting the concept of 'the new-type relations between major powers'. NASA's prevention of Chinese nationals' entry to its facilities really goes against the trend," he added.