Around eight o’ clock in the morning the doorbell of the tiny single room blares, announcing at obscene volume the arrival of breakfast. The person who delivered it is long gone by the time the door opens.

Inside the occupant looks out the window to the grounds of the complex that they aren’t allowed to visit. They wonder how long they have to stay locked up, because no one has told them.

This is life inside Hong Kong’s coronavirus quarantine centres, where new arrivals to the region and those who are “close contacts” of confirmed cases are held until they are deemed not to be carrying the virus.

Hong Kong is routinely praised for getting on top of the initial outbreak of Covid-19 infections, but as the region battles with an emerging second wave of infections, people who have had contact with a confirmed case are receiving alarming phone calls ordering them into government quarantine centres for up to 14 days.

They are told to pack a bag and await collection, which can take as long as 24 hours. In some cases their transport is a bus filled with other potential carriers, taking them all to one of three designated quarantine centres. The centre for health protection has declined to say why it has been transporting people on buses together.

While few are questioning the need for quarantine, the lack of specific information has caused fear and confusion. After learning he had “brief contact” with a confirmed case, British man Paul Ryding self-isolated at his Hong Kong home immediately. Then he received the phone call.

“Don’t believe everything you read about Hong Kong’s laudable or competent response to the #coronavirus outbreak,” wrote Ryding on Twitter.

“Confusion reigns at this particular ‘quarantine camp’ and the inmates here are being treated horrendously.”

As of this minute, I've been sequestered at a "#quarantine camp" by the Hong Kong government for 24 hours. I was made to come here because I had brief contact with a positive case over a week ago. I have so far had no contact whatsoever with any health professional ... — Paul Ryding (@pjrydo) March 21, 2020

Photos from one quarantine centre – a repurposed holiday village – show small rooms with beds crammed in to fit a family, and dirty bathrooms. Some arrivals have their temperature checked by health officers when still on the bus.

One quarantined person told the Guardian they were held in an old building and the rooms were damp and dirty with no hot water. Showers on upper levels leaked into those below.

They described mosquitoes in the rooms and mould on the ceiling. The person said they were not given bottled water for 24 hours.

“The three beds have thin mattresses and are covered in plastic and we have made them up with the damp sheets, everything is damp.”

The sole parent travelling with their two children must also take their temperatures twice a day and phone the results in. They told the Guardian they were “struggling mentally”.

Inside a Hong Kong government quarantine centre. Photograph: Supplied.

Another facility is a newly built apartment complex in Fo Tan, originally intended for low-income subsidised housing. The repurposing of public housing sparked protests, but went ahead anyway.

Reports on the conditions there vary. The rooms are small, even by Hong Kong standards, but some social media users report good food and comfortable conditions. Others have told the Guardian the food is bad and there are not enough blankets.

The complex was used to quarantine the Diamond Princess passengers and those repatriated from Wuhan. Now it holds those coming in from overseas or who have had close contact with a confirmed case, ostensibly to wait in isolation until they get test results.

Ryding claimed on Twitter he was yet to be tested for the virus three days after arrival, and didn’t have contact with a health worker until someone gave him a pen and a thermometer with the instructions to take his temperature twice a day and to call the hotline if it went above 37C.

“It’s very clear to me and others in this situation that I’ve been communicating with (they have had equally dismal experiences here) that we’re not here for medical help or our own good, we’re here because we aren’t trusted to self-isolate, as I had been doing for the last week.”

Four days after he entered the building Ryding posted again, this time showing screenshots of his attempts to get water brought to his room.

Not everyone’s experience is as bad. One woman posted encouraging videos from her quarantine room at Fo Tan, saying the staff were friendly and she felt “safe and in good hands”. “I still feel scared at nights though,” she wrote on her second day.

Reports from as far back as January complain of insufficient information. On government websites there appears to still be no single source explaining who can go where, under what circumstances. Confirmations that “close contact” cases go to mandatory quarantining are scattered across information sheets and government press releases. But that information doesn’t appear to have filtered through to the public.

A Facebook group sharing support and information for people in Hong Kong isolation has grown to more than 2,000 members in a week.

A chemical waste bag inside a Hong Kong government quarantine centre Photograph: Supplied.

Travel advice is more clear: if you are arriving from overseas you must go into 14 days’ isolation. Those arriving from Daegu and Gyeongsangbuk-do in Korea, Iran, or the Italian regions of Emilia-Romagna, Lombardy and Veneto must go to a government centre.

Others can quarantine at home, wearing a tracking wristband connected to authorities. Police have tracked down five absconders in recent days, who face potential prosecution. Another 36 are on the wanted list for alleged breaches. Local close contact cases don’t appear to be given the option of a wristband.

When the Guardian called the health line it was told that close contact cases must go to quarantine centres, but numbers on how many had done so were not available.

The centre for health protection said approximately 1,600 units across the three centres “can be used for quarantine … Currently about 30% of these units are readily available to be used.”