1. "MISCELLANEOUS OFFENCES (PUBLIC ORDER AND NUISANCE) ACT (CHAPTER 184)"
1a) PART II - Excessive noise
14.—(1) Any person who makes any noise by any instrument or other means in such a manner as to cause or be likely to cause annoyance or inconvenience to the occupier of any premises in the vicinity or to any person lawfully using any public road or in any public place shall be guilty of an offence and shall be liable on conviction to a fine not exceeding $1,000.
[10/89]
(2) Any police officer, on any complaint that any person in any premises or in any public place is making such noise as to cause annoyance or inconvenience to the complainant, may enter upon the premises or proceed to the public place and, after warning the person reasonably suspected of making the noise, stop the making of such noise whether by the removal of any instrument or object or in some other appropriate manner.
1b) PART VII - Power of arrest
40.—(1) Subject to the provisions of this Act, any police officer may arrest without warrant any person offending in his view against any of the provisions of this Act, and take him before a Magistrate’s Court to be dealt with according to law.
2. "CHAPTER XIV - OFFENCES AFFECTING THE PUBLIC TRANQUILITY, PUBLIC HEALTH, SAFETY, CONVENIENCE, DECENCY AND MORALS (CHAPTER 224)"
2a) [51/2007] Public nuisance
268. A person is guilty of a public nuisance, who does any act, or is guilty of an illegal omission, which causes any common injury, danger or annoyance to the public, or to the people in general who dwell or occupy property in the vicinity, or which must necessarily cause injury, obstruction, danger or annoyance to persons who may have occasion to use any public right.
Explanation .—A common nuisance is not excused on the ground that it causes some convenience or advantage.
Punishment for public nuisance
290. Whoever commits a public nuisance in any case not otherwise punishable by this Code, shall be punished with fine which may extend to $1,000.
2b) Making atmosphere noxious to health
278. Whoever voluntarily vitiates the atmosphere in any place so as to make it noxious to the health of persons in general dwelling or carrying on business in the neighbourhood or passing along a public way, shall be punished with imprisonment for a term which may extend to one year, or with fine which may extend to $2,500, or with both.
2c) Continuance of nuisance after injunction to discontinue
291. Whoever repeats or continues a public nuisance, having been enjoined by any public servant who has lawful authority to issue such injunction not to repeat or continue such nuisance, shall be punished with imprisonment for a term which may extend to 6 months, or with fine, or with both.
In addition, here is the "TERMS AND CONDITIONS OF APPROVAL FOR EVENTS AND ACTIVITIES CARRIED OUT AT SPEAKERS' CORNER, HONG LIM PARK", which can be found from Npark website.
(1. All events and activities carried out by any approved person at Speakers' Corner, Hong Lim Park, are subject to the terms and conditions stated below and such other terms and conditions as the Commissioner of Parks and Recreation ('the Commissioner') may from time to time impose. The Commissioner reserves the right to cancel any approval or disallow any event or activity at any time without prior notice in the event of any breach of or non-compliance with the terms and conditions herein or where in the Commissioner's opinion the event or activity may endanger or cause discomfort or inconvenience to other park users and/or the general public.)