The prosecutors have protected the identities of the witnesses, who are considered to be “of public interest.”
Addressing Parliament before the vote, Prime Minister Alexis Tsipras said his government would not cover up “one of the biggest scandals in the country’s modern history.”
“Those who enriched themselves from human pain must suffer the consequences,” he said.
All 10 politicians named in the report have denied the accusations, and at least four have sued the witnesses. Most have denounced the affair as a “conspiracy” and a “witch-hunt” by a government, led by the Syriza party, whose popularity is waning a year before general elections.
Five of the accused belong to New Democracy, the main opposition party; three to the Socialist party PASOK; and two are unaligned.
Some of the accused, and many observers, have described the case as an attempt to distract public attention from major foreign policy issues — such as the contentious talks between Greece and neighboring Macedonia over the latter’s name, and rising tensions between Greece and Turkey in the Aegean.
“I did not come here to defend myself, I came to accuse,” Mr. Samaras, who was prime minister from 2012 to 2015, told Parliament, claiming that the government had “called fake witnesses to tarnish its rivals.”
Mr. Pikramenos, who served a one-month term as a caretaker prime minister at the peak of the financial crisis in 2012, teared up during his speech.
“At the beginning I was surprised,” he said. “Now I am overwhelmed by feelings of anger, frustration and disappointment,” he said.
Mr. Stournaras, for his part, spoke of “shameful slander.”
In a written statement sent to Parliament, Mr. Avramopoulos called for the witnesses to be identified and compelled to “answer for their crimes.” He also suggested the investigation was being driven by political motives, noting that the allegations suggest that the bribery “started suddenly in 2006, when I became health minister, and stopped just as suddenly on January 26, 2015,” the day after general elections that brought the current, leftist-led government to power.
Mr. Samaras has sued Mr. Tsipras, who succeeded him in 2015 after campaigning on promises to crack down on the corruption that contributed to Greece’s financial crisis, as well as the country’s deputy justice minister and three prosecutors.
Under Greek law, politicians cannot be directly prosecuted by the judicial authorities. Cases must first be referred to Parliament to investigate, and then lawmakers must revoke immunity before the suspects can be indicted.
The parliamentary investigation is expected to last around a month, and will be further complicated by the fact that the statute of limitations has expired for many of the allegations in the case.
Prosecutors, who were assisted by the F.B.I. in their initial investigation, are seeking to trace the kickbacks alleged to have been pocketed by the politicians, and looking for evidence of money laundering, to which the statute of limitations does not apply.
In a statement earlier this month, when the case file went to Parliament, the firm said it was cooperating “with requests from local and foreign authorities.” The statement added that neither Novartis nor any of its “current associates” had received an indictment in connection with the Greek case.
Novartis has been the subject of several bribery and corruption inquiries — in China, South Korea, Turkey and the United States — in the past three years.