A "litany of errors" contributed to a Hong Kong ferry disaster in which 39 people were killed, an inquiry found Tuesday, slamming the marine department for "systemic failings" in safety standards.

In the city's worst sea disaster in more than 40 years the pleasure boat Lamma IV, carrying more than 120 people, collided with the high-speed Sea Smooth ferry and partially sank within just two minutes near Lamma Island last October.

The inquiry detailed how the bough of the Sea Smooth crashed through the Lamma IV into the main passenger cabin, crushing people as water rushed in.

As the boat tipped up and partially sank some people were trapped by seats that detached and fell on top of them.

The report said government inspectors missed several opportunities to spot the absence of a watertight door within the vessel, which would have stopped the boat sinking so quickly.

"In the process of designing, constructing and surveying the Lamma IV... there was a litany of errors committed at almost every stage by many different people," it said.

"What is required is systemic change, in particular a change in attitude to responsibility and transparency."

The authors criticised the marine department for failing to enforce safety standards, noting that the Lamma IV was carrying no children's life jackets despite being required to do so by law.

Eight children were among those who died in the disaster.

"In respect of general conditions of maritime safety concerning passenger vessels in Hong Kong... there were and are serious systemic failings in the past and present system of control," the report said.

Hong Kong chief executive Leung Chun-ying told a press conference the report revealed "serious problems" in the marine department.

"We must learn the lesson and spare no efforts in making fundamental improvements and reform to ensure marine safety and restore public confidence," he said.

The government will carry out a comprehensive examination of existing controls on marine safety, Leung said, adding that it will conduct disciplinary hearings for any human errors or maladministration found.

The Lamma IV had been travelling to the National Day fireworks display when the collision took place, and Leung announced that this year the display will be suspended, to mark the anniversary of the accident.

Earlier this month the captains of the boats involved in the collision were each charged with 39 counts of manslaughter. Parts of the inquiry report have been redacted to ensure their right to a fair trial.

The disaster shocked the Asian financial hub -- one of the world's busiest ports that prides itself on its safety record -- and more than 100 witnesses testified in the inquiry, led by an independent commission set by up Leung.

Since the accident the city's marine department has been re-inspecting all boats to ensure they meet requirements including lifejacket provision and watertight fittings, said marine director Francis Liu.