The fire engulfed seven residential towers under renovation in the north of the city last week, killing at least 156 people, displacing thousands more and fuelling public demands for accountability.

Of the 156 people confirmed to have died, 29 had yet to be identified, police told reporters on Tuesday. Another 30 people remained unaccounted for.

Police said they had arrested 15 people on suspicion of manslaughter, after an initial probe found that the netting used on exterior scaffolding fell short of fire-resistance standards.

"I will establish an independent committee to conduct a comprehensive and in-depth review to reform the building work system and prevent similar tragedies from occurring in the future," city leader John Lee told a news conference.

The committee will be led by a judge to ensure its independence and credibility, he said.

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

He told AFP that authorities had already identified several failures and pledged reforms to "the whole building renovation system to ensure that such things will not happen again".

While Hong Kong has seen an outpouring of grief, local media reported that several people who were calling for answers and accountability had been arrested.

Icy Luo, a 27-year-old resident who came to the charred Wang Fuk Court housing estate to pray for the victims, told AFP that "the truth of this matter is still far from entirely clear."

- Calls for accountability -

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, including an independent probe, gathered more than 10,000 signatures in less than a day before it was wiped.

Kwan left a police station on Monday, an AFP reporter saw.

Former district councillor Kenneth Cheung was also taken by police, local media reported. He later said he had been released on bail.

Human Rights Watch urged the Hong Kong government on Tuesday to "ensure a transparent investigation and accountability".

"It's crucially important not to treat those demanding answers for the tragic fire as criminals," the group's Asia director Elaine Pearson said, adding that the disaster "raises serious concerns" over Beijing's influence in Hong Kong.

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

Lee added that the upcoming Legislative Council elections set for December 7 would go ahead, after rumours of cancellation.

A press conference of civil society representatives scheduled for Tuesday to discuss government relief efforts and construction regulations was abruptly cancelled, according to an invitation seen by AFP and notifications sent to reporters.

Local media reported that the meeting's initiator Bruce Liu and others were "invited to a meeting" by national security police.

He was later seen leaving a police station.

- 'No longer important' -

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

Ten migrant domestic workers employed at Wang Fuk Court were among the dead, and three others were injured, Hong Kong's labour and welfare chief Chris Sun said.

Families of the foreign victims would each receive around HK$800,000 ($103,000) in compensation, he added.

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

Residents of the only block left unaffected would be allowed to return from Wednesday to collect belongings, government officials told reporters.

Near the wrecked towers, colourful notes bearing heartfelt messages in a subway tunnel were removed by Tuesday afternoon, but appeared on benches and lampposts nearby, AFP reporters saw.

A woman surnamed Leung, 30, wept as she wrote her condolences on a tiny note.

"First of all, there must be an investigation into who must take responsibility, including government officials," Leung told AFP.

But she was pessimistic about that happening under Beijing's oversight.

What people in Hong Kong have to say was "no longer important, because (the government) has a very strong backer", she said.