Prime Minister Datuk Seri Najib Razak wished his Singaporean counterpart Lee Hsien Loong a successful surgery and a speedy recovery.

"Wishing my good friend PM Lee Hsien Loong a successful surgery tomorrow and a full & speedy recovery," he said in his latest posting on Facebook and Twitter.

A statement from the Singapore Prime Minister's office on Sunday said Lee had been diagnosed with prostate cancer and will undergo surgery to remove his prostate gland on Monday.

The robot-assisted keyhole prostatectomy would be carried out by Profv Christopher Cheng, the lead urologist at the Singapore General Hospital (SGH).