Rescue workers pulled a one-year-old girl from the rubble of a building in Kenya's capital on Tuesday more than three days after it collapsed following days of heavy rain.

"The child, who had been buried for about 80 hours, was found in a bucket wrapped in a blanket. She appeared dehydrated, and with no visible physical injuries," the Kenya Red Cross said in a statement.

The fate of her parents was not clear. The girl was being treated in hospital.

At least 26 people have so far been confirmed dead after the six-storey residential block in Nairobi's poor Huruma district crumbled on Friday night.

Police are questioning the building's owners after President Uhuru Kenyatta ordered them detained.

"Three more bodies were retrieved on Tuesday night bringing the number of those confirmed dead to 26," Japheth Koome, Nairobi County police commander, told Reuters.

The girl was brought to the hospital after being found in the ruins of the six-storey building that collapsed Friday night - she had no physical injuries and was being treated for dehydration, according to a hospital spokesman. (Sayyid Abdul Azim/Associated Press)

The collapse of the building was the latest such disaster in a fast expanding African city that is struggling to build homes fast enough.

Like many other cities in Africa, the population of Nairobi has climbed dramatically in recent years. The Kenyan capital had almost 3.5 million people in 2011, about a third bigger than a decade earlier, according to UN figures.

Governments have struggled to provide basic infrastructure and bureaucratic processes to ensure planning rules are met.

Many Kenyans who come to the city in search of work end up in one of several slums, such as Kibera, made up of makeshift homes of wood and corrugated iron sheets.

Others live in slightly better off but still poor districts, like Huruma, where concrete buildings have risen rapidly amid potholed roads and ropey power supplies. Heavy rains have caused other collapses in Nairobi but without such high death tolls. The Interior Ministry said the Huruma building had been earmarked for demolition as it was built close to a river, but the order had not been carried out by local officials. It urged developers to adhere to safety standards.

Rescuers are shown Monday searching for bodies trapped in the rubble at the scene of a collapsed residential building in the low-income suburb of Huruma in Nairobi. At least 26 people died in the collapse. (Tony Karumba/AFP/Getty Images)

After visiting the site on Saturday, Kenya's president ordered other buildings to be surveyed to ensure they were safe.

Rescue workers had said on Monday that the chances of finding more survivors was unlikely. About 136 people have already been saved from the wreck.

Dozens of other people are still listed as missing, Red Cross spokeswoman Arnolda Shiundu said, adding it was not clear how many of those had escaped but had not yet been traced.