President Uhuru Kenyatta and the Inspector General of Police Joseph Boinnet visited the scene of the collapsed six-storey building in Huruma on Saturday morning.
The President ordered for the search and arrest of the owner of the building.
The order came after Nairobi Deputy Governor Jonathan Mueke said the construction of the building had not been approved by City Hall.
The building is said to have had 198 single rooms.
Mr Mueke said up to 70 per cent of residential building in Nairobi do not have formal approvals from City Hall.
The deputy Governor has also ordered residents living in semi-permanent houses near the collapsed building to relocate due to fears that a nearby river could soon burst its banks with the ongoing heavy rains.
The death toll from the collapsed six-storey building has reached seven and the number of injured stands at 121.
“Seven people are confirmed dead and 121 people have been rescued and rushed to various hospitals in Nairobi,” Nairobi county police boss Japheth Koome told Reuters.
By NAIROBI NEWS REPORTER