The protest rally was led by blogger and social activist, Han Hui Hui, 22, and Roy Ngerng, 33, who has been sued by Prime Minister Lee over a matter relating to CPF.
The protesters marched through the carnival yesterday attended by Minister of Trade and Industry Teo Ser Luck at an ongoing performance by a group of special needs children at the Hong Lim Park.
The park is officially dedicated Speaker's Corner which is used to express views and hold carnivals.
PAP or the People's Action Party has been Singapore's ruling political party since 1959.
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The protesters were raising issues relating to CPF money release to account holders. They claim that the government has mismanaged the handling of CPF money.
The group have been organising monthly rallies "Return Our CPF" since June.
Luck told The Sunday Times that he "had to console one of the handicapped children who was frightened by all the heckling".
"We actually planned not to do anything physical to them. We just wanted to spread our message across," Han said.