Natural disasters are no respecters of politics or regimes but it was a cruel twist that made the destructive force of Cyclone Nargis inflict itself upon the benighted people of Burma. Up to 100,000 people are dead or missing as a result of the cyclone’s devastating impact on the Irrawaddy delta and other flood-affected areas. A further 2m are at risk from waterborne disease, hunger and lack of drinking water.

This is a humanitarian crisis on the scale of the Asian tsunami of Boxing Day, 2004. The images flashed to the outside world are, if anything, even more shocking. An entire family lie neatly laid out, all dead, victims of the huge wall of sea water generated by the cyclone. Rotting bodies of people and animals float in the swollen waters. The sight and the smell of death are everywhere.

As after the tsunami, the world wants to help. United Nations agencies have released millions of dollars of funds and charities have sprung into action. Britain’s Disasters Emergency Committee is appealing desperately for donations.

Yet the disaster is being made much worse by the extraordinary and callous attitude of the military junta that has ruled Burma for decades. While its official position is that international help is welcome, it is doing its best to prevent that assistance getting to the people who need it. Planeloads of food aid and equipment have been impounded by the authorities at Rangoon airport and visas for foreign aid workers blocked.

Import duties are being levied on the food being sent to Burma for its starving people. More than a week after the disaster, the vast majority of affected people have yet to receive any help. Amid all the suffering, the authorities appear determined to ensure that they should get the credit for any aid that struggles through.

The attitude of the junta is summed up by its decision this weekend to press ahead with a referendum on constitutional reform. State-run television is telling citizens it is their “patriotic duty” to vote. Apart from the sheer inappropriate-ness of holding a referendum while the country is in the grip of a national disaster, the vote itself is on a sham “road map to democracy” that will merely reinforce the miliary’s grip.

Ban Ki-moon, the UN secretary-general, a persistent critic of the regime in Burma, has warned of “catastrophic” consequences if the aid effort continues to be frustrated. Gordon Brown has said the junta’s obstructive attitude is “utterly unacceptable”, as of course it is. Is there anything the rest of the world can do but condemn?

Even before the disaster Burma was a pariah. The junta’s rule has impoverished its people to the point where it ranks 132nd in the UN human development index. Expenditure on public health is a mere 0.3% of national income. The treatment of Aung San Suu Kyi and other human rights abuses mean that most countries have sanctions in place against Burma. Last September’s brutal crackdown against pro-democracy protesters led to a toughening of those actions.

So the West has limited leverage. China has more influence, but we have yet to see whether Beijing intends to use that influence to get the junta to change its ways. Douglas Alexander, Britain’s international development secretary, says that direct action such as air drops of aid without the permission of the Burmese authorities would be “incendiary”.

Yet something has to be done and done fast. While politicians debate the niceties of dealing diplomatically with an appalling regime, the humanitarian disaster is entering a dangerous second phase, when disease and hunger can claim more lives than the cyclone itself. That cannot be allowed to happen. If it means going over the heads of the authorities and delivering aid directly, the international community must do it. The Burmese junta may be prepared to pretend that it is business as usual and condemn hundreds of thousands of its people to death. The rest of the world cannot allow that to happen.