"We all feel unhappy that (Hong Kong) has come to this and we want things to improve," the 24-year-old student told AFP on Friday while handing out flyers that called for an independent probe into the blaze, which killed at least 146 people this week.

"We need to be frank about how today's Hong Kong is riddled with holes, inside and out."

The demands by Kwan and other organisers turned into an online petition that gained more than 10,000 signatures in less than a day.

However, Hong Kong media reported on Saturday night that Kwan was arrested by national security police on suspicion of sedition and the text of the online petition had been deleted, showing how, under Beijing's watchful eye, dissenting voices in Hong Kong can vanish as quickly as they appear.

Police declined to confirm the arrest on Saturday, saying only that they "will take actions according to actual circumstances and in accordance with the law".

AFP sought further comment from the police on Sunday, while calls to Kwan went unanswered.

Hong Kong was once home to spirited political activism, but that has faded since Beijing imposed a strict national security law in 2020 following huge pro-democracy protests in the Chinese finance hub.

Kwan was reportedly detained not long after Beijing's national security arm in Hong Kong publicly condemned "anti-China forces" for exploiting the disaster and "inciting social division and stirring hatred against authorities".

Asked on Friday if he feared arrest, Kwan said he was only "proposing very basic demands".

"If these ideas are deemed seditious or 'crossing the line', then I feel I can't predict the consequences of anything anymore, and I can only do what I truly believe."

- Grenfell comparisons -

The flyers Kwan and a handful of activists gave out at the train station near the charred residential estate demanded government accountability, an independent probe into possible corruption, proper resettlement for residents and a review of construction oversight.

The demands reflected a belief that the fire was "not an accident" but a man-made disaster, he said.

Authorities have arrested 11 people in connection to the blaze that tore through seven of the eight high-rise blocks of Wang Fuk Court, the world's deadliest residential building fire since 1980.

Hong Kong has previously used judge-led commissions of inquiry to undertake complex fact-finding exercises in a public forum -- a practice left over from British colonial rule.

By contrast, city officials have so far announced only an inter-departmental task force to investigate the blaze.

When Britain was grappling with public fury over the devastating Grenfell Tower fire in 2017, which killed 72 people, the government there announced a public inquiry.

Lawyer Imran Khan, who represented the bereaved and survivors in the inquiry, told AFP "the lessons from Grenfell apply around the world" because all governments need to ensure high-rise residential buildings are safe.

Khan said a public inquiry with court-like powers was a better option for the situation in Hong Kong because "an internal investigation will not get to the truth and there will be no faith in it by the bereaved, survivors and residents".

Based on his experience with Grenfell residents, he said, "without justice they cannot grieve".

Many commuters took the flyers at the Hong Kong station on Friday, although few stopped to chat with Kwan or his companions.

A short walk away near the site of the blaze, a long queue snaked through a park as mourners brought flowers and handwritten notes of remembrance.

One unsigned note left on the ground read: "This is not just an accident, it is the evil fruit of an unjust system, which landed on you. It's not right."