At least 48 people were killed when a truck apparently lost control and plowed into other vehicles and pedestrians at a busy junction in western Kenya on Friday, police said.

Television images showed scenes of devastation at the site of the crash, with the mangled wreckage of several minibusses and the overturned truck as rescuer workers hunted for people feared trapped.

"So far we can confirm 48 dead and we are suspecting one or two are still trapped under the truck," local police commander Geoffrey Mayek told AFP after the accident on the highway between the towns of Kericho and Nakuru.

He said another 30 people had been seriously injured and rushed to various hospitals, warning that the toll could rise.

Tom Mboya Odero, the regional police commander for the Rift Valley, said the truck traveling towards Kericho "lost control and rammed into eight vehicles, several motorcycles, people who were by the roadside, vendors, and other people who were on other businesses."

Kenyan leaders including President William Ruto expressed their condolences after the accident, which took place at around 6:30 pm at a busy area known as Londiani junction.

Transport Minister Kipchumba Murkomen said on Twitter that the rescue efforts would be followed by investigations to determine the cause of the crash.

Collins Kipkoech, a senior doctor at Kericho County Hospital, said his facility's morgue had so far received 45 bodies while more victims were taken to other hospitals "and the rescue is still ongoing".

The Kenyan Red Cross, which sent ambulances and rescue workers to the scene, said heavy rains were hindering rescue operations.

"The truck was on high speed and it was hooting. It tried to avoid several vehicles before it came straight into the market," said one witness, Maureen Jepkoech.

"All I can say is that I am lucky to be alive because I saw what happened and I am alive because I ran, I am just lucky," she added.

"I have seen a very bad scene, bodies and blood all over. So many people are dead."