The move has sparked concern in the country, who said they had not given permission.
His response came after Ramu NiCo Management claimed it had vaccinated 48 Chinese employees.
David Manning, the pandemic response controller in Papua New Guinea, said: “In light of the lack of information of what these trials are and what possible risks or threat that it might cause our people if they were to come into the country, I had cancelled that flight yesterday.”
He added it was “to ensure that we continue to act in the best interests of our people and our country”.
Mr Manning said the National Department of Health had not approved any trials.
He said any vaccines imported into Papua New Guinea “must go through vigorous vaccine trials, protocols and procedures” and must be pre-qualified by the World Health Organisation.
The vaccine was administered to the 48 Chinese in China three days before they landed in Port Moresby, the Pacific nation’s capital, on 13 Aug, the health minister said.
“Details of the vaccine used … are still not known,” Jelta Wong added on Friday.
A document on company paper said 48 Chinese employees “have been vaccinated with Sars-Cov-2 vaccine” on 10 August.
The statement was sent to the Papua New Guinea health department and advised that the vaccine could cause false-positive test results in those who received it, The Australian newspaper reported.
Mr Manning has written to Chinese ambassador Xue Bing seeking “immediate clarification of the Chinese government’s position regarding the vaccination statement”.
Ramu, a Chinese mining company, is operated by a subsidiary of the state-owned China Metallurgical Group Corp.
Australia, which is Papua New Guinea’s largest provider of foreign aid, had learned China may have begun testing a coronavirus vaccine in the region using employees of state-owned enterprises, The Australian reported.
Papua New Guinea – a country of nine million people – has seen a few hundred coronavirus cases to date.
The national death toll stood at four on Friday.
Researchers around the world are conducting trials into a potential coronavirus vaccine in a bid to combat the spread of the virus.
Phone calls to Ramu’s office in the Papua New Guinea city of Madang and to the parent company’s Beijing headquarters were not answered on Friday.
Additional reporting Associated Press