Gui Minhai, a Swedish citizen who has been detained in China off and on for several years, is set to receive an award on Friday from the literary group Swedish PEN, honoring his work as an author and publisher.

Culture Minister Amanda Lind will hand out the prize, even though Gui Minhai won't be present at the ceremony. That has angered the Chinese embassy who say they "firmly oppose" the government's attendance.

If Lind is at the event, the ambassador Gui Congyou said to Radio Sweden China would be forced to take "counter measures", without going into detail about what that would entail.

Speaking on Friday afternoon to news agency TT, the embassy said the Swedish culture minister will be banned from China if she takes part in the PEN awards ceremony.

Gui Minhai was based in Hong Kong and had published books critical of China's leaders. He was abducted while visiting Thailand in 2015 and later appeared in mainland China where he has remained in custody.