A former member of the governing People's Action Party (PAP), he was the Member of Parliament (MP) representing Bo Wen Constituency from 1984 to 1988, the Henderson division of Tiong Bahru Group Representation Constituency (GRC) from 1988 to 1991, and the Radin Mas division of Tanjong Pagar GRC from 1991 to 2001.
[3] In 1984, Vasoo was invited to join the People's Action Party (PAP) by then-Member of Parliament (MP) of Toa Payoh Constituency Eric Cheong.
[4] In the 1984 general election, Vasoo contested for Bo Wen Constiuency and won with 74.70% of the vote against Sh Ahmad Salim of the United People's Front's 25.30%.
[6] During the 1988 general election, after the dissolution of Bo Wen Constituency,[7] Vasoo contested in the Henderson division of the Tiong Bahru Group Representation Constituency (GRC) along with Ch'ng Jit Koon and Chng Hee Kok against the Workers' Party (WP) team of Low Thia Khiang, Lim Lye Soon, and Gopalan Nair.
[9] In 1993, Vasoo held a defamation suit against Singapore Democratic Party's Chee Soon Juan over alleged defamatory remarks made about him and was paid S$210,000 in damages.