Huang Jing, and his wife, Shirley Yang Xiuping, have had their entry permits to Singapore canceled and been labeled "prohibited immigrants," according to the Ministry of Home Affairs.
"Huang used his senior position in the Lee Kuan Yew School of Public Policy to deliberately and covertly advance the agenda of a foreign country at Singapore's expense," a ministry's statement said Friday.
"He did this in collaboration with foreign intelligence agents. This amounts to subversion and foreign interference in Singapore's domestic politics. Huang's continued presence in Singapore, and that of his wife, are therefore undesirable. Both will be permanently banned from re-entering Singapore."
Huang, a US citizen, was a professor on US-China relations at the Lee Kuan Yew School of Public Policy
, situated inside the National University of Singapore.
On his biography, now taken down from the university website
, Huang was described as an "internationally recognized expert on Chinese politics, China's foreign relations and security issues in Asia-Pacific."
He studied at universities in both the United States and China, including Harvard from which he received his doctorate in political science.
Local media the Straits Times said it was the first case of its kind in nearly two decades.
CNN attempted to contact Huang for comment but has not received a response. The ministry did not name the foreign power with which Huang is accused of working.
Ministry: Huang attempted to influence policy
In its statement, Singapore's Ministry of Home Affairs accused Huang of working with intelligence agents from the unnamed foreign country to change policy inside Singapore.
"He engaged prominent and influential Singaporeans and gave them what he claimed was 'privileged information' about the foreign country. ... Huang also recruited others in aid of his operations," the statement alleged.
The ministry claimed some of the information reached senior public officials who would be in a position to change Singapore's public policy. "However, the Singapore government declined to act on the 'privileged information,' " the statement said.
The ministry also accused Huang's wife of being aware of her husband's work to "advance the agenda of a foreign country."
A representative for the National University of Singapore told CNN that Huang had been suspended without pay until the matter was resolved, but he would likely not be able to work at the university due to the revoking of his entry permit.
"This is a matter of serious concern, and (the school) is cooperating fully with (the ministry). (The university) does not tolerate such acts of foreign interference," the representative said.