"Following Miri Regev's appeal to the attorney general to prosecute me and the two MKs who addressed the Australian prisoner affair," Gal-On wrote on her Facebook page, "I would like to suggest that before shouting, Regev learn a thing or two about the duty of lawmakers and the reasons for the existence of parliamentary immunity."
The Meretz MK added, "We Knesset members are here to take care of the public interest – not to come between the public and the authorities and hide information, especially when this information is already published all over the world.
"Miri Regev is using the 'security' excuse to justify silencing and empty incitement. The gag order has nothing to do with a security risk but is aimed at 'not embarrassing' the authorities. The State should really be embarrassed by the fact that Miri Regev, who understands nothing about democracy, reached the position of chief military censor, IDF spokesperson, and worst – Knesset member."
Regev, a former IDF spokeswoman and chief military censor, wrote on her Facebook page on Wednesday morning: "MKs Dov Khenin, Ahmad Tibi and Zahava Gal-On took advantage of their immunity to undermine the State's security.
"I have turned to the Knesset's Ethics Committee to discuss this violation immediately. I will also turn to the attorney general," she warned.
"The MKs violated a gag order. Their remarks helped Israeli and foreign media in complete violation of all codes and agreement between the censor and media outlets."
Australian television network ABC aired an investigation on Tuesday revealing that Ben Zygier, an Australian national who was held in complete isolation at the Ayalon Prison in Ramla, had died in a high-security cell in late 2010. According to official documents, he committed suicide.
The report claimed that in the years before his arrest the man had worked for the Mossad spy agency. The State, the report said, made efforts to keep the case – and the prisoner's existence – a secret.
The 28-minute program revealed that Ben Zygier, who was in his 30s when he died, used the name Ben Alon while living in Israel. He was married to an Israeli woman and had two small children.
According to the investigation, the prisoner was found hanged in a cell which was equipped with state-of-the-art surveillance systems installed to prevent suicide.
According to the ABC inquiry, the case is regarded as one of the most sensitive secrets of Israel's intelligence community, with the government going to extraordinary lengths to stifle media coverage and gag attempts by human rights organizations to expose the situation.
Earlier Wednesday, Internal Security Minister Yitzhak Aharonovitch postponed his Knesset address, which was slated to conclude his term in office. The move was described as "puzzling" by MK Gal-On.
MK Ahamd Tibi (United Arab List-Ta'al) addressed the issue on Twitter, asking: "Could it be that Aharonovitch is suffering from Australian flu?"
In another tweet, he responded to former Foreign Minister Avigdor Lieberman, who accused him of undermining the State's security: "There are those who use their immunity for breach of trust and corruption, and those who do it to maintain the values of freedom and democracy."
During Wednesday's session, Gal-On asked Interior Minister Eli Yishai: "Aren't you concerned by the fact that in Israel of the 21st century people are being held in jail and dying there without the public and its elected representatives knowing anything about it?"
Yishai responded, "I do not know any other law-abiding democratic country like Israel. Many countries in the world can imitate Israel's democracy and envy it."