The creche in a Qatar mall where a fire broke out, killing 19 foreigners including New Zealand triplets, may not have been licensed.
An official in the Social Affairs Ministry says it never issued a permit for Gympanzee, where 13 children and six adults died, Arabic website Al Raya reports.
Qatar's attorney-general has ordered the arrest of five people in connection with the Doha mall fire.
Doha News reports the five include Villaggio mall's owner and the owner of Gympanzee, who is also the daughter of Qatar's Minister of Culture, Arts and Heritage.
The attorney-general has also ordered that the mall manager, the assistant manager and the assistant director of security be detained as part of the investigation, the Doha News website reported.
Doha News had received reports that the mall's manager and assistant manager have been in custody since Monday, but said it could not confirm this.
The attorney-general has also ordered the seizure of documentation critical to the investigation, including operating licenses, it said.
New Zealanders inside the building at the time of the fire have said fire exits were blocked and sprinklers were not working.
Parents make emotional appearance
The arrests come as the dead are mourned in Doha.
A haka was performed as the parents of the two-year-old New Zealand triplets killed made an emotional appearance at an impromptu vigil for the victims of the blaze.
Martin and Jane Weekes joined several hundred locals and
foreigners in a park behind the mall where their children Lillie,
Jackson and Willsher Weekes died.
ONE News Europe correspondent Garth Bray told Breakfast from Doha the vigil was a real outpouring of sentiment from the community.
The mourners gathered around an enormous television screen poised in the middle of the park displaying Twitter messages of condolence and messages put up by the organisers or people who control that area, Bray said.
"But around this place was a heartbreaking collection of flowers," he said.
"What got to me was the children's toys people have been leaving because so many children died - candles, crayons, the sort of things we all give our kids and that they can't give their children any longer. And there were a lot of tears."
Haka draws emotions
Al Jazeera presenter and former Auckland journalist Kamahl Santamaria told Breakfast the Maori karanga and haka was performed for the Weekes and all those who lost their lives and have been affected by the fire.
Santamaria said it was a very emotional moment with not a dry eye anywhere "and the New Zealand community did themselves proud here I think with the way they stepped up."
Jane and Martin Weekes, had been in Qatar for the past five years. They returned to Wellington to give birth to the triplets after they were conceived using IVF. Martin Weekes is a former chief executive of Auckland's Eden Park.
"Lillie, Jackson and Willsher came into this world together and were inseparable as siblings, best friends and the joy of our life," the Weekes family said in a statement emailed to Reuters.
"Tragically they left together after only two short years."
The triplets' grandparents Ron and Jo Turner said they were devastated by the incident and were flying from Wellington to Doha last night to support their family.
A Catholic mass was also held for the fire victims and Bray said one man he spoke to will look into whether families want further public or private memorial services.
A Maori group in Doha is planning a blessing for the Weekes family to try and help ease their pain, he said.
Authorities have ordered an investigation into the blaze amid reports that security staff at the complex reacted slowly to the fire and in chaotic fashion. Several at the complex said fire alarms did not go off or rang only dimly.
Findings from the investigation are expected within a week, and Qatari authorities said late on Monday that a committee would be formed to monitor building safety standards.
Bray said a week seems very short period of time to be getting answers on something like this when it is a reasonably closed community.
The blaze erupted at the mall's Gympanzee nursery on the first floor in a hallway accessible only via a small passage with no emergency fire exit.
Dense smoke and extreme heat created a "death trap" in the corridor as the staircase collapsed, the interior ministry said, making it impossible for rescuers to directly enter the nursery and forcing an evacuation attempt from the building's roof.
The fire raised questions about safety standards in Qatar, the world's largest exporter of liquefied natural gas and one of the richest countries in the world.
"The fire ... is one of the worst tragedies to strike Qatar in living memory and drives home the fact that safety needs to take precedence over everything else when it comes to the country's ambitious future plans," an editorial in the Qatari English-language daily Gulf Times said yesterday.
Bray said people he spoke to at the vigil were worried about building safety standards.
"They are worried I suppose that things go up too fast here and no-one is watching over how well they are looked after afterwards," he said.
Kiwi anger and questions
Santamaria said there has been anger and a lot of questions raised among Doha's Kiwi community.
"You don't expect something like this to happen when you go to the mall...especially as it's such a focal point for the communities here."
Santamaria said because Doha has grown so quickly in recent years, people question whether buildings are going up to the correct standards.
He said much of the discussion has been through social media because the local media is quite limited and is mostly state controlled.
"So of course the rumour and the talk gets fuelled a lot more through the likes of Twitter."