The Petah Tikva District Court extended the gag order on the probe into MK Azmi Bishara until Wednesday.
The court decision was due to the failure of the sides to reach an agreement on which information in the case should be made open to the public.
Bishara's party Balad demanded that the gag order be lifted, claiming that "a partial removal of the gag order allows the police to publish a selective and distorted version, while Balad is prohibited from disclosing details."
The party reiterated its claim that the investigation was aimed at politically destroying Bishara through false accusations in order to silence him.
Meanwhile, Knesset Speaker Dalia Itzik has issued a statement calling on Knesset members to refrain from making racist comments regarding Bishara's resignation.
"This is an isolated case. I call on all Knesset members to refrain from comments that may be insulting to civil servants or different sectors, notably Israeli Arabs, most of whom are law-abiding and loyal citizens," she stated.
Bishara, who left Israel nearly two weeks ago, resigned from the Knesset on Sunday.
According to Foreign Ministry officials, Bishara submitted his resignation letter to Israeli Ambassador to Egypt Shalom Cohen. His faction member, MK Jamal Zahalka, also confirmed the report.
Amnon Meranda, Efrat Weiss and Roee Nahmias contributed to the report