Outgoing Transport Minister Khaw Boon Wan has dengue, his office said yesterday afternoon.

It is the third time he has been stricken with the mosquito-borne disease. His first brush with the virus was in the 1980s.

Mr Khaw, 67, also had a swab test for Covid-19, and the result was negative. He is currently warded in Singapore General Hospital.

He posted on Facebook yesterday morning that he had been admitted to an isolation ward for observation after developing a fever.

Speculating on his condition then, he said: "Unlikely to be Covid, but dengue is possible as my area is a hot zone. Did the swab test just now and hopefully it is a false alarm. I had dengue before, and it was not pleasant."

"Meanwhile, I will just let the body rest and think about retirement!" added Mr Khaw, who announced before the recent general election that he would be retiring from politics.

Mr Khaw lives in the Yio Chu Kang area, which has parts listed by the National Environment Agency as red zones. Red zones are high-risk areas with 10 or more cases.

He only recently finalised negotiations for the Johor Baru-Singapore Rapid Transit System and was looking forward to the signing ceremony.

He said he had also been preparing his office for the next transport minister.