Hongkong Electric yesterday had its fine increased five times to HK$4,500 for deploying three crew members instead of the required four on board the ill-fated Lamma IV boat.
The larger fine came after a magistrate said he had not been fully informed of the details of other convictions when passing the original sentence.
In yesterday's review hearing, prosecutors told Eastern Court the original HK$900 fine did not adequately reflect the seriousness of the offence, as that level of fine had been imposed on smaller vessels which carried fewer passengers than the Lamma IV.
Magistrate David Chum Yau-fong said: "The ship we are talking about is 27 metres long and the maximum number of passengers allowed is 224. On the day [in question], there were 124 passengers in total on the ship."
On October 1 last year, the power firm was taking its workers and their families to view a fireworks display in Victoria Harbour as part of National Day celebrations when its vessel collided with the Hong Kong and Kowloon Ferry-operated Sea Smooth. The tragedy claimed 39 lives.
Earlier, the court heard that the Lamma IV was required to have at least four crew members on board, according to its licence and certificate, but had only three at the time of the incident.
It heard yesterday that the power firm had launched an appeal against its conviction.
Ryan Tsui Chi-shing, who lost his elder brother and niece in the city's worst maritime disaster since 1971, said: "Even if the fine is set at HK$900 or HK$4,500 or HK$4.5 million, that doesn't matter [to the power firm]. Hongkong Electric would have enough money to pay for it anyway.
"The government occupied the moral high ground when it set the fines for the company," he said. "When will the government be strict [with] itself?"
Tsui has long chastised the government for failing to hold any Marine Department officials accountable for the tragedy.
Liberal Party honorary chairwoman Miriam Lau Kin-yee called for a review of the laws and penalties. In August she said the court had "no choice" but to pass sentence based on the law.