Mr Charles Chong, the MP for Punggol East and a political veteran of nearly 30 years, is on eight weeks' medical leave after he underwent "a planned medical procedure" on Thursday, said the People's Action Party (PAP) in a statement yesterday.
It was done at National University Hospital and he is in stable condition, the party said, without disclosing what the procedure was.
Mr Chong, 63, who is also Deputy Speaker of Parliament, expects to gradually resume his constituency activities fully after his medical leave, said the statement.
But his doctors have advised him to limit physical exertion and contact with the public during his recovery, it added.
Mr Chong entered politics in 1988 and is the longest-serving PAP backbencher in Parliament.
Deputy Prime Minister Teo Chee Hean said in the statement that Mr Chong had asked his colleagues in neighbouring Pasir Ris-Punggol GRC, where Mr Teo is the anchor minister, to look after the residents of Punggol East while he recovers.
Meet-the-People Sessions will continue every Monday, except on public holidays and the fifth Monday of a month, and constituency activities will go on as usual.
Mr Teo, who is also Coordinating Minister for National Security, said: "We've always worked together as a team and we will continue to make sure that our Punggol East residents are well looked after."