China faced demands to explain why a state-backed firm claimed it had vaccinated dozens of staff against the coronavirus before sending them back to work at a mine in Papua New Guinea, AFP reported.

The China Metallurgical Group Corporation (MCC) — which controls a major nickel mine in the country — warned local authorities that 48 staff who returned from China this month may test positive for the virus because they had received a vaccine.

In response, Papua New Guinea authorities called for “immediate clarification” from Beijing and blocked a charter flight full of Chinese workers that was due to land on Thursday.

While moving its staff into place, MMC's subsidiary firm Ramu NiCo told Papua New Guinea authorities that any positive coronavirus test results were “the normal reaction of the vaccination and not due to infection”, according to a Chinese and English statement obtained by AFP.