PARIS, Sept 5 (Reuters) - Three French judges are preparing to travel to Ramallah to seek the exhumation Yasser Arafat's body as part of an investigation into whether he was murdered by poison, a judicial source told Reuters on Wednesday.

The investigating magistrates will need approval from both Israel and the Palestinian Authority, but Palestinian President Mahmoud Abbas has already expressed his government's willingness to exhume the body from a limestone sepulcher in Ramallah.

Arafat's widow, Suha, said in a statement sent to Reuters that the judges told her lawyer they had begun the necessary steps to travel to Ramallah, where police experts would carry out tests under their authority.

I respectfully ask the Palestinian Authority and the Arab League to suspend all initiatives while the French justice system is looking into the case, other than to act together with them, Suha Arafat wrote.

The French murder investigation should take precedence over all other procedures, because it is the incontestable guarantee of independence and neutrality, she added.

The court launched the murder inquiry last month into the 2004 death of Arafat in a Paris military hospital after his widow said he may have been poisoned.

No autopsy was carried out after Arafat died, aged 75, a month after being flown to France, seriously ill, from his headquarters in Ramallah.

Allegations of foul play spread quickly after French doctors said they could not establish a cause of death.

Suha Arafat's allegations of poisoning followed a Swiss institute's discovery of high levels of the radioactive element polonium-210 on Arafat's clothing.

The Institute of Radiation Physics in Lausanne said last week it was willing to help conduct a scientific investigation into whether Arafat was poisoned, but that time was of the essence in order to detect traces of the radioactive substance. (Reporting by Thierry Leveque; Writing by Alexandria Sage; Editing by Jon Hemming)