The corner, modelled on its namesake in London's Hyde Park, attracted a flurry of onlookers and reporters, but only a few who ventured to speak. One of the first who did called for the authorities to allow an amplifying system at the site.

The Singapore government, which has strict rules on censorship, announced months ago it would launch the forum because it wanted greater public involvement, conducted in "a mature, non-agitated way."

Critics note that speakers must register for a permit and speeches may be recorded by the police.

The police department said before the corner's opening that uniformed officers would patrol the area twice a day.

Speeches in any of Singapore's four official languages -- English, Mandarin, Tamil and Malay -- cannot be religious in nature or cause hostility among racial or religious groups. The venue, in the city-state's Central Business District, saw larger crowds of onlookers in the afternoon as staff from nearby offices made their way to the venue during their lunch hour.

James Gomez, executive director of the independent Think Centre, gave a speech on how to improve the corner.

Dressed in a black T-shirt with a picture of Malaysia's jailed former deputy prime minister Anwar Ibrahim, he spoke about the need for amplification, which is banned at Speaker's Corner.

When asked about the significance of his T-shirt, he said: "I wanted to make a statement. I wanted people to notice me so I wore something eye-catching."

Anwar, arch-rival of Malaysian Prime Minister Mahathir Mohamad, has been hailed by human rights groups as a prisoner of conscience.

Tan Soo Phuan, disqualified last year in his bid to join the race for Singapore's presidency, railed against the ruling People's Action Party (PAP).

Tan, speaking in Hokkien, a local Chinese dialect, peppered his chat with anti-government slogans to a crowd of about 40.

Overall, the crowd was generally quiet as a small group of about three speakers took the soap box, but some exchanged words with Gomez during his speech.

Gomez said it was a good sign that people were willing to contribute.

A group of Singapore retirees who were part of a Chinese cultural group bemoaned the lack of more speeches in dialects and the lack of shelter from the heat.

"The older folk can't speak Mandarin as fluently as they can dialects, nor can they stand being in the sun for long periods without shelter," a man from the group said in halting English on condition of anonymity.

Singapore has an Internal Security Act (ISA) that permits detention without trial for renewable two-year periods, which authorities say protects against racial and religious extremism, international terrorism, espionage and subversion.

Some critics say it has a chilling effect on testing the limits of government tolerance. Twenty-five speakers had registered to participate today, and some were expected to join later in the day as local temperatures cooled and the audience grew with the close of work.

One man had even registered to speak at the corner for a consecutive 20-day period.