The Health Sciences Authority (HSA) said in a statement on Wednesday that it is aware of an online post making allegations about the actions of its investigation officers.
A Facebook post last Saturday by a Daniel Tan Boon Huat claimed that officers had harassed him and his staff regarding "some administrative issue over our internal shop's transfer of tobacco products", used "intimidation tactics" and knocked on his door on a Saturday night.
In response, HSA said the accusations are false and its officers carried out their duties "professionally, without any harassment or threats made as alleged".
Without naming anyone, HSA said: "The accusations were made by an individual whose tobacco retail licence was suspended because his shop was found selling tobacco to an underage minor.
"This individual and relevant parties are currently assisting HSA in investigations with regard to further violations of the Tobacco Control of Advertisements and Sale Act."
HSA said its officer provided the individual with drinks during his interview at the authority's office on Sept 29, as part of assisting in investigations. Closed-circuit TV footage records showed that the individual also freely left the unlocked interview room several times to attend to personal matters, said HSA.
HSA said its authorised officers visited the relevant parties' homes last Saturday evening and Sunday morning because of new evidence they found during ongoing investigations.
The officers performed their duties professionally by knocking on the door briefly and left when no one was home, it said.
HSA said it takes a serious view of people making unfounded accusations against its authorised officers. It assured the public that its officers will "continue to dutifully conduct themselves professionally and as empowered by the law".