The four-story building collapsed on Sunday, destroying a nearby building and injuring scores of residents.
"The building in question unfortunately had no building permit," Minister Celestine Ketcha Courtes said, adding that an investigation had been launched.
She said rescue efforts were ongoing on Monday to make sure no one was still trapped in the rubble, despite difficult access conditions.
It remained unclear how many occupants were in the building at the time it collapsed. Residents said the building had shown signs of dilapidation with exposed and rusted steel reinforcement rods.
Rescuers were still trying to clear the rubble with a digger after seeking survivors throughout Sunday and into Monday, a resident told AFP.
"The situation is under control and firefighters are working to ensure no one remains under the rubble," Littoral region governor Samuel Dieudonne Ivaha Diboua said Sunday during a visit to the site.
Douala's Laquintinie hospital on Sunday said it had taken in 13 patients, two of whom — a 3-year-old girl and a woman aged 19 — had died.
"The toll could still go up," said computer scientist Prosper Tchinda, who was one of the first on the scene on Sunday.
"There was one survivor who got out with just scratches and we found a baby safe and sound," he told AFP by telephone.
The 42-year-old lives a few minutes walk from the block and said there had been "some sort of event with music going on when it happened."
Nathalie, who also lives in the area but did not want to give her full name, described the building as in a poor state with "failings."
"There were cracks in the wall and we felt it could collapse at any time," she said. "It was not the sort of place you would want to live in."
Natalie said she went to the site immediately after hearing "a big noise," and confirmed that a party had been going on.
Tchinda said he was "very worried."
"There are so many buildings that don't meet the standards. Each one goes up built any how without any checks.
"You have the impression that the appropriate services at city hall are not doing their job," he added.
Five people died in similar circumstances in Douala in 2016 when authorities blamed the poor state of repairs and apparent violations of building regulations.
In June that year, local authorities identified 500 buildings in danger of collapse.
Information for this report came from AFP and Reuters.