Two people have been confirmed dead and 26 others pulled from the rubble after a four-storey building collapsed at Mwembe area in Kisii town Wednesday morning.
The National Disaster Management Unit Communications Officer Pius Maasai said 30 more people could be trapped in the debris.
He said 24 people have been hospitalised and that Kenya Defence Forces have been called in to assist in the rescue operation.
Earlier, the County Disaster boss Julius Tinega told reporters at the scene that the building was under construction and more than 25 workers are believed to have already reported to work at the time.
"So far we have pulled out between 10 and 12 people and we have brought more personnel and equipment to aid in the (rescue) operation," he said.
He said more people were still trapped in the rubble.
Four people were pulled from the rubble when rescue operations begun at 8.30am in the morning by first emergency responders, among them bodaboda operators.
Mr Julius Orare, who lives in a residential near the collapsed building said he was in the shower when he heard tremors. He went to check and saw the building had collapsed.
Mr John Omori , another witness, said he was on his way to work at 8.15am when he saw the building collapsing.
"There were some people on top when the building came tumbling down,' he said.
At least two women said their husbands had already reported to work at the site and they are yet to know if they have been rescued.
The incident comes barely a year after a seven- floor building collapsed in central Kisii killing eight people.
Kisii Governor Mr James Ongwae visited the scene and is expected to issue a statement.