As per the request made by the panel, the Home department on August 23 issued a notification granting the extension, he said.
The committee, headed by IPS officer Aswathi Dorjee, was set up for conducting a departmental inquiry of Jadhav.
The panel had on June 25 sought an extension of three months to submit the report, the official said.
Other members on the committee are: Assistant Commissioner of Police Arvind Sawant, advocate Anupama Pawar, activist Farida Lambe, and Deputy Superintendent of Yerwada Jail Aruna Mugutwar.
He later filed a writ petition in the High Court against his suspension.