Veteran Member of Parliament Inderjit Singh is retiring from politics.

The Ang Mo Kio GRC MP announced the move in a Facebook post last night addressed to residents and grassroots leaders of his Kebun Baru ward in the GRC.

He thanked them for their support, confidence and trust in him.

"I did my best to serve, and this would not have been possible without my team, the grassroots leaders and branch activists at Kebun Baru, who have become my extended family," he said.

Changes to electoral boundaries announced earlier saw the ward being moved from Ang Mo Kio GRC to Nee Soon GRC.

Mr Singh, 55, told The Straits Times his decision was not a hasty one. He asked to step down on Jan 2, 2013. He had approached Prime Minister Lee Hsien Loong, the secretary-general of the People's Action Party and a fellow Ang Mo Kio GRC MP, with his request.

The businessman entered politics in the 1997 General Election, during which he and the PAP team were elected unopposed in Ang Mo Kio GRC.

In his 18 years as an MP, he made some hard-hitting speeches on the impact of economic restructuring, foreign labour curbs and rising business costs on small businesses. In 2007, he also warned of overcrowding and soaring costs as a result of the national growth policy.

His likely replacement is food-supply company executive director Henry Kwek, 39, who has been shadowing him at community events. Mr Kwek commented on the MP's farewell post, and thanked him for all he had done .

Said Mr Singh: "To Kebun Baru, Ang Mo Kio and everyone there, you will always be in my heart."