Kean - who met with reporters Monday to address the issue - said Sweeney's action was unprecedented, according to the Associated Press.
Kean accused Sweeney of punishing Republicans who, amid an intraparty battle, stuck by him in his bid to remain minority leader, the AP reported.
A spokesman for Kean said he was unavailable Monday afternoon. Spokesmen for Sweeney said he had no comment.
The two Senate leaders have been publicly at odds in recent months. Kean attacked Sweeney this spring for not posting Republican bills after a procedural dispute over gun legislation Sweeney supported.
Kean made a high-profile bid to defeat Sweeney in last month's elections, backing the Democrat's Third District opponent, Republican Niki Trunk.
Sweeney taunted Kean after the Nov. 5 election for the Republicans' failure to pick up a single seat in the Democratic-controlled Senate.
When Kean was chosen by his caucus to remain minority leader - surviving a challenge from Kevin O'Toole (R., Passaic) - Sweeney issued a biting statement: "I could ask for no better minority leader than the one whose own strategy cemented their place as the minority party."
As Kean accused Sweeney on Monday of punishing Republicans for choosing Kean over O'Toole, a memo dated Dec. 13 suggests Kean also may have tried to target his rivals.
Outlining his planned allocations of the $330,000 he apparently expected to receive from the leadership fund, Kean intended to give $10,000 to O'Toole - $15,000 less than he received this past year, according to records shared with The Inquirer.
The Newark Star-Ledger reported Monday that Kean said he would not discuss his allocation to O'Toole.