Four hundred pupils had to stay home yesterday after their upmarket kindergarten was shut suddenly for failing to comply with fire regulations.
The closure of Cannan International Kindergarten in Cumberland Road, Kowloon Tong, triggered a row after it emerged the school had been unlicensed without parents' knowledge for at least 10 months.
Parents were phoned at home on Thursday night and told there would be no school after the Education Department reported the matter to police and ordered the kindergarten to close.
The Education Department admitted it was aware last March that the school was not registered because it had failed to meet fire safety requirements.
A spokesman said that since then it had investigated the kindergarten's unregistered status and issued three warning letters.
But parents were not told of the problem until Thursday.
The kindergarten will be allowed to re-open after carrying out the necessary work, believed to involve installing sprinklers.