The building that was under construction at Mwembe on Kisii-Kilgoris road collapsed at around 8:15am killing two workers on the spot, with dozens others buried alive in the rubble.
It is believed that about 25 people were working at the site when the incident happened.
Kisii county disaster management team leader Julius Tinega said on Wednesday evening that rescue efforts were underway and that 24 people had been pulled out of the rubble.
Cases of building collapsing are increasingly becoming frequent in the country amid concerns that greedy developers are bypassing building regulations to lower costs and maximise returns.
In November last year, a 10-storey building that was under construction collapsed in Kisii town killing 6 people. The building was the second in less than six years to collapse in the neighbourhood that is considered as a wetland.