While Dr Tony Tan delivered his two-minute Nomination Day speech, crowds could be heard jeering as he spoke.
Dr Tan had waited for a few seconds, but the crowd did not quieten down before he proceeded to speak.
In his speech, he said he wanted to reach out to Singaporeans to share his vision of the Presidency with them.
When he made a request for the crowd to reach out to their friends and loved ones to make a distinction between the Presidential Election and the General Election, the boo-ing could be heard reaching a crescendo.
According to The Straits Times, the jeers came from a vocal group of people who mostly supported Mr Tan Jee Say.
The hecklers went on to chant "Patrick Tan, Patrick Tan", the name of Dr Tan's son, who had drawn criticism for his 12-year disruption from NS.
In a later press conference, Dr Tan said that he was disappointed that some refused to listen to another andidate, even though different viewpoints are to be expected in a campaign.
He said: "I don't think that jeering or heckling is the right way to go about the campaign, particularly in a campaign for the president, which has to be conducted with decorum and dignity."
Dr Tan Cheng Bock and Mr Tan Kin Lian have also voiced their disapproval of the crowd's boo-ing.
Mr Tan Jee Say said he could not be sure if the boo-ing came from his supporters, and that boo-ing was "not the correct way to conduct this campaign".