Forty-five Ethiopians were arrested in two separate places in the ongoing operation against human trafficking.
Four Kenyan suspects believed to be behind the trafficking were also arrested and are facing charges in court, police said.
The first group of 32 was arrested in Loitoktok area, Kajiado as they planned to cross the border to Tanzania.
According to police, they were alerted there were aliens in Kiwanja Ndege area and moved there to check on the same.
Of the male group, 17 hid in a quarry site while the rest were in a house near the area.
Head of Transnational Organized Crime Unit George Mutonya said a Kenyan woman who was harbouring the group was also arrested in the Wednesday operation.
He said the suspect would face charges of harbouring foreigners and human trafficking.
Mutonya said they are looking for the woman’s husband for grilling over the same offences.
In Isebania area, Migori, 13 other Ethiopians were arrested in a village while also planning to cross to Tanzania.
Police said all the suspects were men and had been in the area for three days while waiting to be facilitated to cross the border.
The Ethiopian nationals were arrested for being in Kenya without proper documentation and will be charged with the offence of being unlawfully present in Kenya.
Also arrested were four Kenyans, three male adults and one female adult to be charged with the offence of harbouring aliens and facilitating the movement of aliens, police said.
These are the latest such arrests to happen.
Dozens of Ethiopians are arrested in the country as they try to use this route to other places like Tanzania, the Middle East and South Africa.
Police and immigration officials have decried increased cases of Ethiopian aliens nabbed in the country while in transit.
Officials from the Transnational Organized Crime Unit are conducting joint operations to deal with the issue of human smuggling.
Tens of Ethiopians are annually arrested in Kenya while in transit and later deported. Most of those arrested come to Kenya to seek jobs or are in transit.
What is puzzling is how the immigrants manage to evade many police roadblocks mounted from the Moyale border where they use to Nairobi.
There are more than 20 roadblocks on the stretch, which raises the seriousness of the security agents taming the practice.