The 47 victims could be buried in common grave.
President Uhuru Kenyatta and his Deputy William Ruto, are among other influential State officials that will grace the ceremony.
Earlier, reports indicated that the 47 could be buried in a common grave.
The memorial service comes in the wake of heightened pressure from a section of Senators who have demanded the arrest of the owner of the dam, Mr Mansukul Patel.
The Committee on National Security and Foreign Relations also wants the Water Resources Management Authority (WRMA) disbanded for laxity in discharging its mandates.
The committee, chaired by Garissa Senator Yusuf Haji, also said that Mr Patel should be arrested for negligence.
On Monday, the committee toured the scene of the disaster to establish the devastating effects of the calamity.
Nakuru Senator Susan Kihika called WRMA a “toothless dog.” Kihika, also a member of the committee, urged police to arrest Patel like they have done to owners of collapsed buildings.
"I can't believe this is a natural disaster. It is a man-made. It's baffling that a week later, the dam owner has not been arrested or made to recorded statement with police," Kihika stated.
"This person [Patel] is behaving as if he is above the law. Maybe he is."
Haji asked the government to relocate the 150 families sheltered at Solai Boys High School, saying the camp was congested.
"There would be another serious disaster in case of a disease outbreak at the camp. That's why the government must act without delay," Haji said.