At least 44 people were killed when the reservoir on the farm, which grew roses for export to Europe, burst its banks on Wednesday night after heavy rains. Another 40 people have been reported missing.
The public prosecutor's office said on Twitter the police chief had been ordered "to carry out thorough investigations to establish cause and culpability if any" behind the disaster and file a report within two weeks.
The Daily Nation newspaper quoted government officials as saying the dam and others on the 3,500-acre Solai farm, 190 km (120 miles) northwest of Nairobi, had not been cleared by government engineers.
Villagers had also complained when the dams were built, accusing the farm-owner of depriving them of access to river water, the paper reported.
Vinoj Kumar, general manager of the farm, blamed the dam wall collapse on torrential rain in a forest above the dam and denied that it was defective or had not received the necessary approvals.
"How can they say it is illegal?" he told Reuters. "It was not built today or yesterday. It was built 20 years back."
As muddy brown water coursed through the dirt road running through the village of Solai, police at a checkpoint waved through lorries filled with sacks of rice brought by the Kenyan Red Cross.
At the village health centre, distraught doctor Veronica Achoka recounted the "untold suffering" of the community since Wednesday night when the dam burst.
At the hospital in the nearby town of Bahati, dozens were being treated with injuries ranging from fractures to internal bleeding, she said.
Government engineers drained water from a second dam to prevent another collapse.
Kenya's cut-flower sector, in the fertile Rift Valley, has grown dramatically in the last decade to become one of the biggest foreign exchange earners in East Africa's largest economy and a major source of employment.
After a severe drought last year, East Africa has been hit by two months of heavy rain that has affected nearly a million people in Kenya, Somalia, Ethiopia and Uganda. Bridges have been swept away and roads turned into rivers of mud.
More than 150 people have been killed and 300,000 displaced in Kenya, where roads, bridges and crops have been swept away, causing millions of dollars of damage.
"We all breathed a sigh of relief when the rainy season started strong in early March," said Lane Bunkers of Catholic Relief Services in Kenya.
"But now - two months later - we are seeing the consequences of the drought-ravaged land's inability to absorb all the rain due to its degraded state."
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)