The head of the Electoral Affairs Commission, Barnabas Fung, said there were four unmarked votes among the 1,428 cast in the Chief Executive election.
He told reporters they were declared invalid without the adjudication of returning officers.
"The four invalid votes were votes which have no choice appending on them," he said. "According to the law, they are invalid ballots."
He said the ballot-counting process took about 23 minutes, adding that the result was announced at 12:28pm – less than an hour after voting ended.
Fung said the commission is very satisfied with Sunday's voting arrangements. "The election was conducted in an open, just and honest manner," he said.
He added that all ballots and relevant documents will be kept for six months.
Meanwhile, the Electoral Affairs Commission will conduct a detailed review of various electoral arrangements and submit a report to the chief executive, in accordance with the law.