Jurong GRC MP Tan Wu Meng was attacked by a 32-year-old man during his Meet-the-People Session (MPS) in Clementi on Monday night.
Dr Tan, 42, told The Straits Times yesterday that he was talking to a resident at around 10pm when a young man dashed towards him and began hitting him with his fists.
"One moment I was speaking to the resident and the next thing I knew, someone was hitting me and I found myself on the floor," he said.
The attacker was restrained by residents and volunteers.
Dr Tan, a medical oncologist, had bruises on his arm and abrasions on his neck, and the police and Singapore Civil Defence Force officers, who arrived soon after, advised him to go to the hospital to have his condition evaluated.
He said he was not keen to go as a handful of residents had yet to see him. "I saw them before I went to the hospital."
The attacker was arrested by the police for criminal trespass and is also being investigated for voluntarily causing hurt to an MP.
"Whatever the outcome under the law, I hope he can get back on track and I will try to help him do so," Dr Tan said in a Facebook post yesterday.
After his check-up at National University Hospital on Monday night, he returned to the MPS to continue writing appeal letters for residents - including his attacker.
The attacker had been to his MPS once, about a year ago, Dr Tan said. This time, he attacked the MP before he could be interviewed "but we were able to piece together" his current problem and "wrote an appeal for him last night".
Dr Tan, a first-term MP, said no such incident had ever happened to him before but, as a public servant, he was always aware it could.
He added: "The work continues."
Attacks on MPs are rare. They have happened twice and, both times, involved former MP Seng Han Thong. In 2009, he was at a grassroots event when a 70-year-old man splashed paint thinner on his back and lit a flame, causing burns on his face and upper body.
In 2006, he was punched at his MPS by a 74-year-old cabby who felt the MP was not helping him get back his revoked taxi licence.
Dr Tan does not plan to beef up security at his MPS area.
He feels it is quite secure, and he wants the area to remain accessible to residents. "There is always someone nearby and we have CCTV cameras in the room," he added.
Deputy Prime Minister Tharman Shanmugaratnam, leader of the team of MPs in Jurong GRC, said in a Facebook post that it was "very unfortunate that this happened - and completely unacceptable".
He wrote that Dr Tan and his volunteers handled the incident well. "But as Wu Meng says, we will find a way to help this young man get back in life eventually."
The organising secretary of the People's Action Party, Mr Chan Chun Sing, said Dr Tan's calm handling of the incident helped to reassure his volunteers and residents.
Mr Chan, who is also the labour chief and Minister in the Prime Minister's Office, added in his statement: "This is a stark reminder of the risks our MPs have to manage in the course of our public duties.
"We would also like to thank our many volunteers who work tirelessly as a team to serve our residents and take care of each other."
The police said a 32-year-old man will be charged in court today. The Straits Times understands that he was previously involved in drug-related offences.