Palestinian officials have long alleged that Israel poisoned Arafat. Israel has always denied that it played any role in Arafat's death, and repeated that statement Thursday.
The Israeli energy minister, Silvan Shalom, who was foreign minister and a member of Israel's "security cabinet" in 2004, said, "We never made a decision to harm him physically."
Shalom told Israel Radio: "In my opinion, this is a tempest in a tea cup. But even if it was [poisoning], it certainly was not Israel. Maybe someone else inside had thoughts or an interest to do it."
Arafat's widow, Suha, called on the Palestinian leadership to seek justice for her husband.
Speaking from Doha, Qatar, on Thursday, she told a reporter that only countries with nuclear capabilities have access to polonium. She did not specifically mention Israel.
The findings from specialists at the University of Lausanne were released Wednesday in a 108-page report and posted online by the al-Jazeera television network, which commissioned the study, together with Suha Arafat.
The Swiss document appears to provide the first clear-cut sign that Arafat did not die of natural causes. But its authors framed their analysis cautiously, saying the results "moderately support the proposition" that polonium-210 - a colorless, odorless and nearly impossible to detect isotope - killed him.
The Swiss analysis took into account the time lapse since Arafat's death and the nature and quality of the specimens examined.
Arafat fell ill in October 2004 and was airlifted to France days later, after he failed to respond to treatment from a team of medical specialists from the Middle East. In early November, he lapsed into a gradually deepening coma, and died November 11.
In a separate and still controversial case that arose two years later, British investigators directly linked polonium-210 to the poisoning death of one-time Russian spy Alexander Litvinenko, who had defected to London. From his death bed, Litvinenko said he believed Kremlin leader Vladimir Putin was to blame for his imminent death.
Russia later denied British requests to hand over a key suspect in the investigation of Litvinenko's murder. The case remains open.