An Indonesian man who entered Singapore waters illegally was among the Covid-19 patients whose cases were announced on Thursday.

The Ministry of Health (MOH) said the man entered Singapore waters from Indonesia without valid documentation, and was arrested by the Police Coast Guard.

"He was tested for Covid-19 infection, and isolated until he was conveyed to the hospital when his result came back positive," said MOH.

The man, aged 26, did not show symptoms. He was confirmed positive on Wednesday. The ministry did not say when he was arrested.

He was among the seven new imported cases reported on Thursday.