Israel poisoned the late Yasser Arafat with the lethal radioactive substance polonium, a nephew of the veteran Palestinian leader alleged on Thursday.

"We accuse Israel of killing Yasser Arafat by poisoning him with that lethal substance," Nasser al-Qidwa told AFP, referring to polonium, traces of which were recently found on clothing worn by the ailing leader.

"Those responsible for that assassination should be held accountable and judged," said Qidwa, who is also president of the Yasser Arafat Foundation.

Allegations that the veteran Palestinian leader, who died in a French hospital in November 2004, was poisoned were resurrected earlier this month after Al-Jazeera news channel broadcast an investigation in which experts said they had found high levels of polonium on his personal effects.

Polonium is a highly-toxic substance which was used to kill former Russian spy turned Kremlin critic Alexander Litvinenko in 2006. He died after drinking a cup of tea laced with the substance at a London hotel.

Francois Bochud, head of the Institute of Radiation Physics at the University of Lausanne which conducted the tests, told Al-Jazeera that "significant polonium" had been found on Arafat's effects, but that his remains would need to be tested to confirm the theory that he had been poisoned.

Senior Palestinian officials have said they would agree to an exhumation of the body, which is buried in Ramallah, if the family gave its permission, and Qidwa on Thursday said they would raise no objections.

"The Arafat Foundation contacted the Swiss laboratory and informed them that it had no objection to analysing samples from the body of the late Palestinian president Yasser Arafat if it is necessary," he said.

At the time of his death, Palestinian officials charged that Arafat, 75, had been poisoned by Israel, but an inconclusive investigation a year later ruled out cancer, AIDS or poisoning.