The investigating agency Monday issued notice to Information Technology Minister Ponnala Lakshmaiah directing him to appear before it on June 7, CBI sources said.
The minister would be appearing before CBI on the day when five-day CBI custody of jailed MP Jaganmohan Reddy would come to an end.
Lakshmaiah, as minister for major industries in the earlier cabinet of Y.S. Rajasekhara Reddy, had issued orders allocating water from Krishna river to some cement companies which invested in the companies of Rajasekhara Reddy's son Jaganmohan Reddy.
The CBI on May 24 arrested then excise minister Mopidevi Venkataramana. He is now lodged in Chanchalguda Central Jail.
Venkataramna had issued orders allotting land and extending other concessions for Vanpic company, whose promoter Nimmagadda Prasad made investments in Jagan's companies.
Lakshmaiah will be the fourth minister to be questioned by the CBI in the case. The agency had already questioned Home Minister Sabita Indra Reddy and Roads and Buildings Minister Dharmana Prasada Rao. Two other ministers are also under the CBI scanner.
The Supreme Court in March had issued notices to the six ministers and eight Indian Administrative Service (IAS) officials, asking them why their role should not be probed in issuing 26 controversial government orders during YSR's tenure.