At least 47 Ethiopians have been arrested while being transported to Mombasa in a truck.
They were nabbed when police stopped the truck at Makindu in Makueni county for inspection.
The truck supposed to drop the aliens in Voi at a fee.
Makindu police boss Jashon Poloh said they had no documents and they will be interrogated to establish their mission.
He said the group is lucky to have not suffocated.
“We have had incidents of people transported in enclosed lorries suffocate. These ones are lucky,” Poloh said.
He added they will seek to repatriate the group back to their country.
The Ethiopians said the were headed to South Africa for greener pastures.
They were to pass through the Taita Taveta border to Tanzania and find a smuggler to deliver them to Mozambique and later to South Africa.
The smuggler behind the group was not found but efforts to trace him are ongoing, police said.
The driver of the truck was arrested as police continue with their investigations.
This is the latest such incident to happen in the area. Police said most of the aliens use the Moyale route on their way to South Africa and the Middle East, oblivious of the dangers ahead.
Police and immigration officials have decried increased cases of Ethiopian and Eritrean aliens arrested in the country while on transit.
Officials from the Transnational Organised Crime Unit are conducting joint operations to deal with human smuggling.
What is puzzling is how the immigrants manage to evade the more than 20 police roadblocks on their way to Nairobi.
As part of efforts to deal with the problem, an Ethiopian national was sentenced to 31 years in prison for trafficking 12 fellow Ethiopian immigrants in Nairobi.
Yibekal Gatachew, alias Adinan Mohamed Galano, was sentenced by a Kahawa West Law Court on September 7 last year.
He had been arrested on November 3, 2021 in Ngumo estate, Nairobi.