Iran's death toll from the Saudi hajj disaster has nearly doubled to 464 pilgrims killed, state media reported today, a development that is likely to further strain ties between the Middle East arch-rivals.

It was not immediately clear how the rise in the Islamic Republic's death toll, announced on the website of Iranian state television, would affect the overall toll from the September 24 disaster near Islam's holy city of Mecca.

Saudi Arabia's Health Ministry reported on Saturday that the crush and stampede killed at least 769 pilgrims and injured 934, but Pakistan, India, Indonesia and Iran all have suggested the true casualty figures may be higher.

Saudi state media and officials had no immediate comment on the Iranian announcement, though they say they are investigating what caused the crush and stampede in Mina.

The disaster has fed into the bitter regional rivalry between the Sunni Saudi Arabia and the Shiite Iran, which back opposite sides in the wars in Syria and Yemen.

On Wednesday, Iran's Supreme Leader Ayatollah Ali Khamenei warned of "harsh" measures if the kingdom failed to promptly repatriate the bodies of the Islamic Republic's dead.

"The Saudi government is not carrying out its obligation to repatriate and in some cases shows slyness," Mr Khamenei told military commanders in northern Iran in comments broadcast on state TV.

"The Islamic Republic of Iran has so far showed self-restraint, observed Islamic decency and brotherly respect in the Islamic world, but they should know that Iran's hand is superior to many others and has more capabilities."

"If (Iran) wants to react to disturbing and sinister elements, their situation will not be good," Mr Khamenei added.

Iran has led a chorus of international criticism directed at Saudi Arabia's response to the incident, saying its diplomats were not given access to victims until days after the stampede. That is a criticism also levied by Indonesia, the Muslim world's most populous country.

Iranians have staged daily protests near the Saudi Embassy in Tehran, and President Hassan Rouhani devoted a significant part of his speech at the UN General Assembly on Monday to blaming Saudi authorities for the disaster and demanding it be "fully investigated".

Indonesia, Pakistan and India all have said their diplomats received some 1,100 pictures of the dead in the hajj disaster, suggesting a higher death toll than what Saudi officials have announced. Saudi Arabia said Tuesday that the photos are of those who died during the entire pilgrimage and not just at the disaster just outside Mecca.

The accusations of mismanagement of the pilgrimage strike at a key pillar of the Saudi royal family's prestige, with King Salman holding the title of the "custodian of the two holy mosques".