Authorities have said the blaze, which was the city's worst fire in decades, spread quickly via netting used on exterior scaffolding that fell short of fire-resistance standards and failed to stop flames from spreading.

"I will establish an independent committee to conduct comprehensive and in-depth review to reform the building work system and prevent similar tragedies from occurring in the future," the city's leader John Lee told a news conference in English, adding that the committee would be led by a judge.

Hong Kong has a legal mechanism to set up "commissions of inquiry", which in the past were usually led by judges to undertake complex fact-finding exercises -- a practice left over from British colonial rule.

Lee used a different term, "independent committee", on Tuesday.

Lee told AFP that authorities had identified several failures, and that reforms would be needed in safety, supervision, construction and maintenance standards.

"We must act seriously to ensure that all these loopholes are plugged so that those who are responsible will be accountable. The shortcomings will be addressed. The bottlenecks will be addressed," he said.

"We will reform the whole building renovation system to ensure that such things will not happen again."

Hong Kong's anti-corruption watchdog and police, running a joint investigation, have arrested a total of 14 people, 13 of them on suspicion of manslaughter over the blaze.

"The responsible culprits tried to mix up substandard net with qualified nets so as to cheat inspection and law enforcement agencies," Lee said, calling the suspects "evil".

The city has seen a massive outpouring of grief as well as calls for accountability, but local media reported the arrests of several people who were calling for answers.

Miles Kwan, a 24-year-old student, was reportedly arrested by police for "seditious intent" after handing out flyers demanding government accountability.

An online petition containing Kwan's four demands, which included calls for an independent probe, gathered more than 10,000 signatures in less than a day before its contents were wiped.

Two other people, including former district councillor Kenneth Cheung, were also taken in by police, according to local media reports.

Asked about the arrests, Lee told AFP that "I will not tolerate any crimes, particularly crimes that exploit the tragedy that we have been facing now".

The world's deadliest residential building fire since 1980 broke out on Wednesday at the high-rises of Wang Fuk Court in the city's northern Tai Po district.

Police completed searches in five of the seven affected towers on Monday, finding the remains of victims in apartments, hallways and stairs.

Some families of victims returned to Wang Fuk Court on Monday to begin traditional funeral rites, which are expected to continue.