The Director of Immigration, Au Ka-wang; the Commissioner of Customs, Hermes Tang; and the Undersecretary for Security, Sonny Au were each fined HK$5,000 for attending a hotpot dinner at a private club in Wan Chai in March.
The matter was only exposed by media recently.
Speaking on a radio programme, Lee said the officials had apologised and borne the legal consequences of their mistake.
“They know they’re negligent and that the incident has caused public concern. They should improve and be more alert,” Lee said.
“This incident shows everyone should be careful about what they do. Experience leads to wisdom,” he said.
He said he believed they would be more careful about their actions in future.
The police said it was during an investigation into a criminal case that they found out about the dinner on March 2, and nine people had been fined for violating rules on group gatherings.
A man was later arrested and charged with attempted rape.
The Police Commissioner, Raymond Siu, refused to comment on the controversy and whether the three officials were invited to assist in the investigation of the rape case.