Kluang MP Liew Chin Tong has been diagnosed with Bell's palsy, a facial nerve paralysis which causes a temporary muscular weaknesses on one side of the face.

In a Facebook posting today, he said the paralysis was caused by an inflammatory condition during a mild fever he suffered between Dec 27 and Jan 7.

"If you happen to bump into me and see an unsmiling face, it's not rudeness. It's Bell's palsy.

"The condition makes it difficult for me to read for too long, especially on screen; resulting in speech difficulty (can’t pronounce certain sounds at the moment); and a straight face that cann’t smile for now!" Liew wrote.

The DAP political education bureau director cited his doctor as saying that full recovery might take up to three months.

In the meantime, he said he will do more reflection and writing and hopes to be back in action within the next two weeks.