IEBC Chief Executive Officer James Oswago on Friday said although the date is tentative, the commission is ready to hold the mini-poll that was occasioned by the death of Mutula Kilonzo.
Oswago said that the budget has already been sent to the Treasury for approval.
“Although the law provides that we hold the by-election within 90 days, we are already ahead in the planning and should roll-out our programme by next week.
“The Treasury did not have a budget for by-elections but we have already drafted our budgets and are waiting for them,” he added.
Senate Speaker Ekwe Ethuro declared the Makueni Senate seat vacant on Thursday, a week after the former Education Minister was buried at his Mbooni home.
The late Kilonzo who ran on a Wiper Democratic Movement ticket emerged victorious beating former Kilome MP Harun Mwau of the Party of Independent Candidates of Kenya (PICK).
Makueni County comprises six constituencies namely Mbooni, Kaiti, Kilome, Makueni, Kibwezi East and Kibwezi West.
Kilonzo was found dead three weeks ago at his Maanzoni ranch home.
The mystery surrounding the death of the senator still lingers with results expected earliest in July.
Pathologists who carried out a post-mortem on the body of the late Kilonzo on April 30 said that they needed between eight to 10 weeks to make a conclusive finding on the cause of death.